SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    1665, 1661, 1659, 1622, 1651, 1614, 1666, 
    1657, 1648, 1676, 323, 327, 308
  )

Query time 0.00092

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_categories",
      "access_type": "range",
      "possible_keys": ["parent"],
      "key": "parent",
      "key_length": "3",
      "used_key_parts": ["parent_id"],
      "rows": 13,
      "filtered": 100,
      "index_condition": "cscart_categories.parent_id in (1665,1661,1659,1622,1651,1614,1666,1657,1648,1676,323,327,308)"
    }
  }
}