SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    282, 272, 266, 285, 287, 276, 278, 290
  ) 
  AND category_id != 264

Query time 0.00024

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": 35.87786102,
          "attached_condition": "cscart_categories.parent_id in (282,272,266,285,287,276,278,290) and cscart_categories.category_id <> 264"
        }
      }
    ]
  }
}