SELECT 
  products.company_id, 
  COUNT(DISTINCT products.product_id) as products_count 
FROM 
  cscart_products as products 
  LEFT JOIN cscart_product_descriptions as descr1 ON descr1.product_id = products.product_id 
  AND descr1.lang_code = 'en' 
  LEFT JOIN cscart_product_prices as prices ON prices.product_id = products.product_id 
  AND prices.lower_limit = 1 
  LEFT JOIN cscart_companies AS companies ON companies.company_id = products.company_id 
  INNER JOIN cscart_products_categories as products_categories ON products_categories.product_id = products.product_id 
  INNER JOIN cscart_categories ON cscart_categories.category_id = products_categories.category_id 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
  AND cscart_categories.storefront_id IN (0, 1) 
  LEFT JOIN cscart_warehouses_sum_products_amount as war_sum_amount ON war_sum_amount.product_id = products.product_id 
  LEFT JOIN cscart_warehouses_destination_products_amount AS warehouses_destination_products_amount ON warehouses_destination_products_amount.product_id = products.product_id 
  AND warehouses_destination_products_amount.destination_id = 0 
  AND warehouses_destination_products_amount.storefront_id = 0 
WHERE 
  1 = 1 
  AND companies.status IN ('A') 
  AND products.company_id IN (2, 64, 92, 103, 104, 121, 127, 0) 
  AND (
    CASE products.is_stock_split_by_warehouses WHEN 'Y' THEN warehouses_destination_products_amount.amount ELSE products.amount END
  ) > 0 
  AND products.status IN ('A') 
  AND (
    products.usergroup_ids = '' 
    OR FIND_IN_SET(0, products.usergroup_ids) 
    OR FIND_IN_SET(1, products.usergroup_ids)
  ) 
  AND products.status IN ('A') 
  AND prices.usergroup_id IN (0, 0, 1) 
  AND products.parent_product_id = 0 
  AND products.product_type != 'D' 
  AND products.company_id IN (64, 2, 92, 103, 104) 
GROUP BY 
  products.company_id

Query time 0.00006

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "war_sum_amount",
          "access_type": "system",
          "possible_keys": ["PRIMARY"],
          "rows": 0,
          "filtered": 0,
          "const_row_not_found": true
        }
      },
      {
        "table": {
          "table_name": "warehouses_destination_products_amount",
          "access_type": "system",
          "possible_keys": ["PRIMARY", "idx_storefront_id"],
          "rows": 0,
          "filtered": 0,
          "const_row_not_found": true
        }
      },
      {
        "read_sorted_file": {
          "filesort": {
            "sort_key": "products.company_id",
            "table": {
              "table_name": "products",
              "access_type": "ALL",
              "possible_keys": ["PRIMARY", "status", "idx_parent_product_id"],
              "rows": 67,
              "filtered": 79.83960724,
              "attached_condition": "products.parent_product_id = 0 and products.company_id in (2,64,92,103,104,121,127,0) and case products.is_stock_split_by_warehouses when 'Y' then NULL else products.amount end > 0 and products.`status` = 'A' and (products.usergroup_ids = '' or find_in_set(0,products.usergroup_ids) or find_in_set(1,products.usergroup_ids)) and products.product_type <> 'D' and products.company_id in (64,2,92,103,104)"
            }
          }
        }
      },
      {
        "table": {
          "table_name": "prices",
          "access_type": "ref",
          "possible_keys": [
            "usergroup",
            "product_id",
            "lower_limit",
            "usergroup_id"
          ],
          "key": "usergroup",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "ref": ["ebonza_cscart_test.products.product_id"],
          "rows": 1,
          "filtered": 90.5405426,
          "attached_condition": "prices.lower_limit = 1 and prices.usergroup_id in (0,0,1)",
          "using_index": true
        }
      },
      {
        "table": {
          "table_name": "companies",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "4",
          "used_key_parts": ["company_id"],
          "ref": ["ebonza_cscart_test.products.company_id"],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "companies.`status` = 'A'"
        }
      },
      {
        "table": {
          "table_name": "products_categories",
          "access_type": "ref",
          "possible_keys": ["PRIMARY", "pt"],
          "key": "pt",
          "key_length": "3",
          "used_key_parts": ["product_id"],
          "ref": ["ebonza_cscart_test.products.product_id"],
          "rows": 1,
          "filtered": 100
        }
      },
      {
        "table": {
          "table_name": "cscart_categories",
          "access_type": "eq_ref",
          "possible_keys": ["PRIMARY", "c_status", "p_category_id"],
          "key": "PRIMARY",
          "key_length": "3",
          "used_key_parts": ["category_id"],
          "ref": ["ebonza_cscart_test.products_categories.category_id"],
          "rows": 1,
          "filtered": 100,
          "attached_condition": "(cscart_categories.usergroup_ids = '' or find_in_set(0,cscart_categories.usergroup_ids) or find_in_set(1,cscart_categories.usergroup_ids)) and cscart_categories.`status` in ('A','H') and cscart_categories.storefront_id in (0,1)"
        }
      }
    ]
  }
}