SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    22893, 22896, 22880, 22881, 22890, 22879, 
    22883, 22885, 22889, 22892, 22887, 
    22886, 22897, 22894, 22899, 22882, 
    22895, 22888, 22891, 22898, 22884
  ) 
  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 (22893,22896,22880,22881,22890,22879,22883,22885,22889,22892,22887,22886,22897,22894,22899,22882,22895,22888,22891,22898,22884)",
          "attached_condition": "cscart_categories.category_id <> 1"
        }
      }
    ]
  }
}