SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    166, 167, 203, 223, 219, 228, 241, 245, 
    250, 293, 294, 265, 296, 297, 298, 299, 
    300, 301, 302, 303, 304, 305, 306
  ) 
  AND category_id != 264

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_categories",
          "access_type": "ALL",
          "possible_keys": ["PRIMARY", "parent", "p_category_id"],
          "rows": 131,
          "filtered": 44.27481079,
          "attached_condition": "cscart_categories.parent_id in (166,167,203,223,219,228,241,245,250,293,294,265,296,297,298,299,300,301,302,303,304,305,306) and cscart_categories.category_id <> 264"
        }
      }
    ]
  }
}