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 (
    951, 950, 949, 948, 947, 946, 945, 944, 
    943, 942, 941, 940, 939, 938, 937, 936, 
    935, 932, 931, 930, 929, 928, 927, 919, 
    918, 917, 517, 516, 515, 478, 477, 476, 
    475, 474, 464, 460, 434, 433, 432, 431, 
    428, 427, 424, 423, 422, 421, 420, 419
  )

Query time 0.00301

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "67.21"
    },
    "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": 48,
          "rows_produced_per_join": 48,
          "filtered": "100.00",
          "index_condition": "(`wearethehelpful_scalesta_net`.`p`.`product_id` in (951,950,949,948,947,946,945,944,943,942,941,940,939,938,937,936,935,932,931,930,929,928,927,919,918,917,517,516,515,478,477,476,475,474,464,460,434,433,432,431,428,427,424,423,422,421,420,419))",
          "cost_info": {
            "read_cost": "28.81",
            "eval_cost": "4.80",
            "prefix_cost": "33.61",
            "data_read_per_join": "768"
          },
          "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": [
            "wearethehelpful_scalesta_net.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 48,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "12.00",
            "eval_cost": "4.80",
            "prefix_cost": "50.41",
            "data_read_per_join": "18K"
          },
          "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": [
            "wearethehelpful_scalesta_net.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 48,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "12.00",
            "eval_cost": "4.80",
            "prefix_cost": "67.21",
            "data_read_per_join": "4K"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      }
    ]
  }
}