SELECT 
  product_id, 
  group_id 
FROM 
  cscart_product_variation_group_products 
WHERE 
  group_id IN (
    631, 745, 630, 629, 50, 52, 54, 47, 203, 
    975, 213, 204, 87, 55, 92, 90, 94, 201, 
    227, 239, 85, 76, 89, 527, 415, 202, 221, 
    228, 217, 234, 207, 235, 326, 215, 325, 
    328, 538, 257, 241, 570, 803, 536, 205, 
    330, 230, 244, 211, 808, 539, 568, 959, 
    970, 972, 1029, 991, 973
  )

Query time 0.00222

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "166.11"
    },
    "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": 338,
      "rows_produced_per_join": 338,
      "filtered": "100.00",
      "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_variation_group_products`.`group_id` in (631,745,630,629,50,52,54,47,203,975,213,204,87,55,92,90,94,201,227,239,85,76,89,527,415,202,221,228,217,234,207,235,326,215,325,328,538,257,241,570,803,536,205,330,230,244,211,808,539,568,959,970,972,1029,991,973))",
      "cost_info": {
        "read_cost": "132.31",
        "eval_cost": "33.80",
        "prefix_cost": "166.11",
        "data_read_per_join": "5K"
      },
      "used_columns": [
        "product_id",
        "group_id"
      ]
    }
  }
}