SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    285, 275, 296, 287, 203, 269, 219, 250, 
    297, 270, 298, 271, 299, 272, 274, 301, 
    302
  )

Query time 0.00070

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_categories",
      "access_type": "ALL",
      "possible_keys": ["parent"],
      "rows": 34,
      "filtered": 70.588,
      "attached_condition": "cscart_categories.parent_id in (285,275,296,287,203,269,219,250,297,270,298,271,299,272,274,301,302)"
    }
  }
}