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 (
    7909, 7941, 7255, 8066, 8545, 9446, 9820, 
    7491, 7907, 7911, 7915, 7936, 9879, 
    7494, 7557, 7566, 8257, 8547, 9858, 
    7502, 7560, 7561, 7725, 7896
  )

Query time 0.00098

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "37.06"
    },
    "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": 27,
          "rows_produced_per_join": 27,
          "filtered": "100.00",
          "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`p`.`product_id` in (7909,7941,7255,8066,8545,9446,9820,7491,7907,7911,7915,7936,9879,7494,7557,7566,8257,8547,9858,7502,7560,7561,7725,7896))",
          "cost_info": {
            "read_cost": "15.46",
            "eval_cost": "2.70",
            "prefix_cost": "18.16",
            "data_read_per_join": "432"
          },
          "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": 27,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "6.75",
            "eval_cost": "2.70",
            "prefix_cost": "27.61",
            "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": 27,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "6.75",
            "eval_cost": "2.70",
            "prefix_cost": "37.06",
            "data_read_per_join": "2K"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      }
    ]
  }
}

Result

feature_id purpose product_id parent_product_id id code
682 group_variation_catalog_item 7907 0 788 PV-FBC443152
682 group_variation_catalog_item 7909 0 789 PV-A9E5D1F1C
682 group_variation_catalog_item 7911 0 790 PV-11D3DE0C0
682 group_variation_catalog_item 7936 0 791 PV-F2CCD740E
682 group_variation_catalog_item 7941 0 792 PV-AFB319B66
682 group_variation_catalog_item 8257 0 797 PV-20B7EC393
682 group_variation_catalog_item 9446 0 891 PV-56A5FB89B
682 group_variation_catalog_item 9820 0 909 PV-218717443
682 group_variation_catalog_item 9858 0 913 PV-0C0F078BB
682 group_variation_catalog_item 9879 0 918 PV-69AF9C7BF