SELECT 
  id_path 
FROM 
  cscart_categories 
WHERE 
  category_id IN (
    1, 24, 33, 49, 53, 67, 73, 76, 80, 81, 91, 
    222, 223, 224, 233, 234, 261, 306
  )

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_categories",
      "access_type": "range",
      "possible_keys": ["PRIMARY"],
      "key": "PRIMARY",
      "key_length": "3",
      "used_key_parts": ["category_id"],
      "rows": 18,
      "filtered": 100,
      "index_condition": "cscart_categories.category_id in (1,24,33,49,53,67,73,76,80,81,91,222,223,224,233,234,261,306)"
    }
  }
}