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 (
    87041, 87093, 87094, 87095, 87096, 87097, 
    87098, 87099, 84638, 84639, 84636, 
    84637, 91014, 91026, 91038, 91051, 
    84506, 84507, 84572, 84573, 84661, 
    84662, 89057, 84504, 84505, 84570, 
    84571, 89059, 89060, 84634
  )

Query time 0.00046

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "1.05"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "f",
          "access_type": "ALL",
          "possible_keys": [
            "idx_group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.25",
            "eval_cost": "0.10",
            "prefix_cost": "0.35",
            "data_read_per_join": "104"
          },
          "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": [
            "nuie_scalesta_net.f.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "0.25",
            "eval_cost": "0.10",
            "prefix_cost": "0.70",
            "data_read_per_join": "400"
          },
          "used_columns": [
            "id",
            "code"
          ]
        }
      },
      {
        "table": {
          "table_name": "p",
          "access_type": "ref",
          "possible_keys": [
            "PRIMARY",
            "idx_group_id"
          ],
          "key": "idx_group_id",
          "used_key_parts": [
            "group_id"
          ],
          "key_length": "3",
          "ref": [
            "nuie_scalesta_net.f.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 1,
          "filtered": "100.00",
          "index_condition": "(`nuie_scalesta_net`.`p`.`product_id` in (87041,87093,87094,87095,87096,87097,87098,87099,84638,84639,84636,84637,91014,91026,91038,91051,84506,84507,84572,84573,84661,84662,89057,84504,84505,84570,84571,89059,89060,84634))",
          "cost_info": {
            "read_cost": "0.25",
            "eval_cost": "0.10",
            "prefix_cost": "1.05",
            "data_read_per_join": "16"
          },
          "used_columns": [
            "product_id",
            "parent_product_id",
            "group_id"
          ]
        }
      }
    ]
  }
}