SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    227, 208, 138, 6, 3560, 10, 2893, 49, 2, 
    2907, 198, 225, 2486, 70, 188, 2975, 
    3145, 3781
  )

Query time 0.00149

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_categories",
      "access_type": "ALL",
      "possible_keys": ["parent"],
      "rows": 2628,
      "filtered": 30.13698578,
      "attached_condition": "cscart_categories.parent_id in (227,208,138,6,3560,10,2893,49,2,2907,198,225,2486,70,188,2975,3145,3781)"
    }
  }
}