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 (
    6925, 6946, 6953, 6954, 6960, 6962, 6972, 
    7016, 7056, 7088, 7112, 7123, 7135, 
    7137, 7145, 7149, 7150, 7178, 7180, 
    7205, 7296, 7299, 6875, 6884, 6895, 
    6965, 6973, 6999, 7001, 7057, 7091, 
    7103, 7163, 7187, 7188, 7199, 7304, 
    7313, 6916, 6922
  )

Query time 0.00070

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "56.01"
    },
    "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": 40,
          "rows_produced_per_join": 40,
          "filtered": "100.00",
          "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`p`.`product_id` in (6925,6946,6953,6954,6960,6962,6972,7016,7056,7088,7112,7123,7135,7137,7145,7149,7150,7178,7180,7205,7296,7299,6875,6884,6895,6965,6973,6999,7001,7057,7091,7103,7163,7187,7188,7199,7304,7313,6916,6922))",
          "cost_info": {
            "read_cost": "24.01",
            "eval_cost": "4.00",
            "prefix_cost": "28.01",
            "data_read_per_join": "640"
          },
          "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": 40,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "10.00",
            "eval_cost": "4.00",
            "prefix_cost": "42.01",
            "data_read_per_join": "15K"
          },
          "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": 40,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "10.00",
            "eval_cost": "4.00",
            "prefix_cost": "56.01",
            "data_read_per_join": "4K"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      }
    ]
  }
}