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 (
    6606, 6607, 6608, 6610, 6611, 6612, 6613, 
    3024, 3025, 3026, 3027, 3301, 6847, 
    3300, 2841, 2842, 2843, 2844, 6426, 
    6427, 6428, 6429, 6430, 2765, 2766, 
    2767, 2768, 6352, 6353, 6354, 6355, 
    6356, 2185, 2186, 2187, 2188, 5785, 
    5786, 5787, 5788, 5789, 6641, 6219, 
    5807, 3722, 5819, 1516, 6623, 1504, 
    1494, 6209, 1499, 1489, 1433, 6614, 
    2268, 2269, 2270, 2271, 2336, 2337, 
    2338, 2339, 2412, 2413, 2414, 2415, 
    2416, 2417, 2418, 2419, 2420, 2514, 
    2515, 2516, 2517, 2518, 2604, 2605, 
    2606, 2607, 3840, 3841, 3842, 3843, 
    5867, 5868, 5869, 5870, 5871, 5935, 
    5936, 5937, 5938, 5939, 6012
  )

Query time 0.00115

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "336.01"
    },
    "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": 96,
          "rows_produced_per_join": 96,
          "filtered": "100.00",
          "index_condition": "(`test2_gaseus`.`p`.`product_id` in (6606,6607,6608,6610,6611,6612,6613,3024,3025,3026,3027,3301,6847,3300,2841,2842,2843,2844,6426,6427,6428,6429,6430,2765,2766,2767,2768,6352,6353,6354,6355,6356,2185,2186,2187,2188,5785,5786,5787,5788,5789,6641,6219,5807,3722,5819,1516,6623,1504,1494,6209,1499,1489,1433,6614,2268,2269,2270,2271,2336,2337,2338,2339,2412,2413,2414,2415,2416,2417,2418,2419,2420,2514,2515,2516,2517,2518,2604,2605,2606,2607,3840,3841,3842,3843,5867,5868,5869,5870,5871,5935,5936,5937,5938,5939,6012))",
          "cost_info": {
            "read_cost": "57.61",
            "eval_cost": "9.60",
            "prefix_cost": "67.21",
            "data_read_per_join": "1K"
          },
          "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": [
            "test2_gaseus.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 96,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "24.00",
            "eval_cost": "9.60",
            "prefix_cost": "100.81",
            "data_read_per_join": "37K"
          },
          "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": [
            "test2_gaseus.p.group_id"
          ],
          "rows_examined_per_scan": 7,
          "rows_produced_per_join": 672,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "168.00",
            "eval_cost": "67.20",
            "prefix_cost": "336.01",
            "data_read_per_join": "68K"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      }
    ]
  }
}