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 (
    1909, 1145, 1127, 1126, 1125, 1124, 1123, 
    1111, 1110, 1109, 1108, 1107, 1053, 
    1051, 1050, 1049, 1048, 960, 959, 958, 
    957, 941, 940, 939, 929, 928, 927, 919, 
    918, 917, 517, 516, 515, 424, 423, 422, 
    421, 420, 419, 373, 351, 350
  )

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "58.81"
    },
    "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": 42,
          "rows_produced_per_join": 42,
          "filtered": "100.00",
          "index_condition": "(`wearethehelpful_scalesta_net`.`p`.`product_id` in (1909,1145,1127,1126,1125,1124,1123,1111,1110,1109,1108,1107,1053,1051,1050,1049,1048,960,959,958,957,941,940,939,929,928,927,919,918,917,517,516,515,424,423,422,421,420,419,373,351,350))",
          "cost_info": {
            "read_cost": "25.21",
            "eval_cost": "4.20",
            "prefix_cost": "29.41",
            "data_read_per_join": "672"
          },
          "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": 42,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "10.50",
            "eval_cost": "4.20",
            "prefix_cost": "44.11",
            "data_read_per_join": "16K"
          },
          "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": 42,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "10.50",
            "eval_cost": "4.20",
            "prefix_cost": "58.81",
            "data_read_per_join": "4K"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      }
    ]
  }
}