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 (
    2478, 2527, 2490, 2471, 2576, 2620, 2502, 
    2473, 2565, 2580, 2550, 2599, 2503, 
    2602, 2540, 2685, 2623, 8398, 2499, 
    2581
  )

Query time 0.00101

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "29.16"
    },
    "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": 21,
          "rows_produced_per_join": 21,
          "filtered": "100.00",
          "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`p`.`product_id` in (2478,2527,2490,2471,2576,2620,2502,2473,2565,2580,2550,2599,2503,2602,2540,2685,2623,8398,2499,2581))",
          "cost_info": {
            "read_cost": "12.36",
            "eval_cost": "2.10",
            "prefix_cost": "14.46",
            "data_read_per_join": "336"
          },
          "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": 21,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "5.25",
            "eval_cost": "2.10",
            "prefix_cost": "21.81",
            "data_read_per_join": "8K"
          },
          "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": 21,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "5.25",
            "eval_cost": "2.10",
            "prefix_cost": "29.16",
            "data_read_per_join": "2K"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      }
    ]
  }
}

Result

feature_id purpose product_id parent_product_id id code
656 group_variation_catalog_item 2471 0 201 PV-00D965C97
648 group_variation_catalog_item 2471 0 201 PV-00D965C97
656 group_variation_catalog_item 2473 0 202 PV-4F29F9E11
656 group_variation_catalog_item 2478 0 203 PV-B1468472B
648 group_variation_catalog_item 2478 0 203 PV-B1468472B
656 group_variation_catalog_item 2490 0 204 PV-2B3485D42
648 group_variation_catalog_item 2490 0 204 PV-2B3485D42
656 group_variation_catalog_item 2499 0 205 PV-73BE8BF5C
656 group_variation_catalog_item 2502 0 415 PV-A9D4992E1
656 group_variation_catalog_item 2503 0 207 PV-5DA198C96
643 group_variation_catalog_item 2527 0 213 PV-A39282D9A
656 group_variation_catalog_item 2527 0 213 PV-A39282D9A
648 group_variation_catalog_item 2527 0 213 PV-A39282D9A
656 group_variation_catalog_item 2540 0 215 PV-773B8A180
656 group_variation_catalog_item 2550 0 217 PV-E6E15F2B3
648 group_variation_catalog_item 2550 0 217 PV-E6E15F2B3
656 group_variation_catalog_item 2565 0 221 PV-A655EE32D
656 group_variation_catalog_item 2576 0 227 PV-89AEEFC38
656 group_variation_catalog_item 2580 0 228 PV-D71C0663F
656 group_variation_catalog_item 2581 0 230 PV-02AE72AF3
656 group_variation_catalog_item 2599 0 234 PV-38D7AEC40
648 group_variation_catalog_item 2599 0 234 PV-38D7AEC40
643 group_variation_catalog_item 2602 0 235 PV-6B0B1F6F7
656 group_variation_catalog_item 2602 0 235 PV-6B0B1F6F7
648 group_variation_catalog_item 2602 0 235 PV-6B0B1F6F7
656 group_variation_catalog_item 2620 0 239 PV-BDCC0B960
643 group_variation_catalog_item 2623 0 241 PV-8D16C295C
656 group_variation_catalog_item 2623 0 241 PV-8D16C295C
648 group_variation_catalog_item 2623 0 241 PV-8D16C295C
656 group_variation_catalog_item 2685 0 257 PV-A9B46B73A
656 group_variation_catalog_item 8398 0 803 PV-BA339DA79
648 group_variation_catalog_item 8398 0 803 PV-BA339DA79