SELECT 
  f.feature_id, 
  f.purpose, 
  p.product_id, 
  p.parent_product_id, 
  g.id, 
  g.code 
FROM 
  cscart_product_variation_group_features AS f 
  INNER JOIN cscart_product_variation_groups AS g ON f.group_id = g.id 
  INNER JOIN cscart_product_variation_group_products AS p ON f.group_id = p.group_id 
WHERE 
  p.product_id IN (
    8545, 9217, 9241, 9324, 9446, 9704, 9820, 
    10494, 10499, 10505, 10514, 7087, 7177, 
    7433, 7446, 7491, 7530, 7666, 7907, 
    7911, 7915, 7936, 8679, 9523
  )

Query time 0.00080

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "35.91"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "p",
          "access_type": "range",
          "possible_keys": [
            "PRIMARY",
            "idx_group_id"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "product_id"
          ],
          "key_length": "3",
          "rows_examined_per_scan": 26,
          "rows_produced_per_join": 26,
          "filtered": "100.00",
          "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`p`.`product_id` in (8545,9217,9241,9324,9446,9704,9820,10494,10499,10505,10514,7087,7177,7433,7446,7491,7530,7666,7907,7911,7915,7936,8679,9523))",
          "cost_info": {
            "read_cost": "15.11",
            "eval_cost": "2.60",
            "prefix_cost": "17.71",
            "data_read_per_join": "416"
          },
          "used_columns": [
            "product_id",
            "parent_product_id",
            "group_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "g",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "id"
          ],
          "key_length": "3",
          "ref": [
            "softwarepirmam_hewadelivard_cscart_4.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 26,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "6.50",
            "eval_cost": "2.60",
            "prefix_cost": "26.81",
            "data_read_per_join": "10K"
          },
          "used_columns": [
            "id",
            "code"
          ]
        }
      },
      {
        "table": {
          "table_name": "f",
          "access_type": "ref",
          "possible_keys": [
            "idx_group_id"
          ],
          "key": "idx_group_id",
          "used_key_parts": [
            "group_id"
          ],
          "key_length": "3",
          "ref": [
            "softwarepirmam_hewadelivard_cscart_4.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 26,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "6.50",
            "eval_cost": "2.60",
            "prefix_cost": "35.91",
            "data_read_per_join": "2K"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      }
    ]
  }
}