SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    22694, 22707, 22691, 22692, 22700, 22704, 
    22709, 22708, 22703, 22697, 22706, 
    22690, 22710, 22702, 22693, 22695, 
    22698, 22696, 22705, 22699, 22701
  ) 
  AND category_id != 1

Query time 0.00003

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_categories",
          "access_type": "range",
          "possible_keys": ["PRIMARY", "parent", "p_category_id"],
          "key": "parent",
          "key_length": "3",
          "used_key_parts": ["parent_id"],
          "rows": 21,
          "filtered": 100,
          "index_condition": "cscart_categories.parent_id in (22694,22707,22691,22692,22700,22704,22709,22708,22703,22697,22706,22690,22710,22702,22693,22695,22698,22696,22705,22699,22701)",
          "attached_condition": "cscart_categories.category_id <> 1"
        }
      }
    ]
  }
}