SELECT 
  category_id, 
  parent_id 
FROM 
  cscart_categories 
WHERE 
  parent_id IN(
    2960, 2964, 2963, 2962, 2961, 2972, 2966, 
    2965, 2967, 2973, 2969, 2968, 2971, 
    2970
  ) 
  AND category_id != 414

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "9.81"
    },
    "table": {
      "table_name": "cscart_categories",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "parent",
        "p_category_id"
      ],
      "key": "parent",
      "used_key_parts": [
        "parent_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 14,
      "rows_produced_per_join": 14,
      "filtered": "100.00",
      "index_condition": "(`s2cart`.`cscart_categories`.`parent_id` in (2960,2964,2963,2962,2961,2972,2966,2965,2967,2973,2969,2968,2971,2970))",
      "cost_info": {
        "read_cost": "8.41",
        "eval_cost": "1.40",
        "prefix_cost": "9.81",
        "data_read_per_join": "49K"
      },
      "used_columns": [
        "category_id",
        "parent_id"
      ],
      "attached_condition": "(`s2cart`.`cscart_categories`.`category_id` <> 414)"
    }
  }
}