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 (
    1447, 1426, 1437, 1460, 1464, 1421, 1462, 
    1409, 1416, 1472, 1452, 1425, 1438, 
    1424, 1413, 1450, 1469, 1455, 1443, 
    1418, 1634, 1664, 1641, 1671, 1627, 
    1657, 1655, 1686, 1646, 1677, 1636, 
    1666, 1638, 1668, 1644, 1674, 1642, 
    1672, 2185, 1629
  )

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "2.33"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "f",
          "access_type": "ALL",
          "possible_keys": [
            "idx_group_id"
          ],
          "rows_examined_per_scan": 2,
          "rows_produced_per_join": 2,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.52",
            "eval_cost": "0.20",
            "prefix_cost": "0.72",
            "data_read_per_join": "208"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      },
      {
        "table": {
          "table_name": "g",
          "access_type": "eq_ref",
          "possible_keys": [
            "PRIMARY"
          ],
          "key": "PRIMARY",
          "used_key_parts": [
            "id"
          ],
          "key_length": "3",
          "ref": [
            "cscartdevel.f.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 2,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.50",
            "eval_cost": "0.20",
            "prefix_cost": "1.42",
            "data_read_per_join": "800"
          },
          "used_columns": [
            "id",
            "code"
          ]
        }
      },
      {
        "table": {
          "table_name": "p",
          "access_type": "ALL",
          "possible_keys": [
            "PRIMARY",
            "idx_group_id"
          ],
          "rows_examined_per_scan": 2,
          "rows_produced_per_join": 4,
          "filtered": "100.00",
          "using_join_buffer": "hash join",
          "cost_info": {
            "read_cost": "0.51",
            "eval_cost": "0.40",
            "prefix_cost": "2.33",
            "data_read_per_join": "64"
          },
          "used_columns": [
            "product_id",
            "parent_product_id",
            "group_id"
          ],
          "attached_condition": "((`cscartdevel`.`p`.`group_id` = `cscartdevel`.`f`.`group_id`) and (`cscartdevel`.`p`.`product_id` in (1447,1426,1437,1460,1464,1421,1462,1409,1416,1472,1452,1425,1438,1424,1413,1450,1469,1455,1443,1418,1634,1664,1641,1671,1627,1657,1655,1686,1646,1677,1636,1666,1638,1668,1644,1674,1642,1672,2185,1629)))"
        }
      }
    ]
  }
}