SELECT 
  product_id, 
  group_id 
FROM 
  cscart_product_variation_group_products 
WHERE 
  group_id IN (
    260, 433, 195, 571, 305, 261, 364, 363, 
    404, 352, 418, 252, 155, 266, 383, 432, 
    373, 382, 366, 399, 688, 374, 304, 401, 
    365, 461, 463, 462
  )

Query time 0.00067

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "31.76"
    },
    "table": {
      "table_name": "cscart_product_variation_group_products",
      "access_type": "range",
      "possible_keys": [
        "idx_group_id"
      ],
      "key": "idx_group_id",
      "used_key_parts": [
        "group_id"
      ],
      "key_length": "3",
      "rows_examined_per_scan": 55,
      "rows_produced_per_join": 55,
      "filtered": "100.00",
      "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_variation_group_products`.`group_id` in (260,433,195,571,305,261,364,363,404,352,418,252,155,266,383,432,373,382,366,399,688,374,304,401,365,461,463,462))",
      "cost_info": {
        "read_cost": "26.26",
        "eval_cost": "5.50",
        "prefix_cost": "31.76",
        "data_read_per_join": "880"
      },
      "used_columns": [
        "product_id",
        "group_id"
      ]
    }
  }
}