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 (
    5623, 5624, 5625, 5626, 5627, 5628, 5629, 
    5630, 5631, 5632, 5633, 5634, 5635, 
    5636, 5637, 5638, 5639, 5640, 5641, 
    5642, 5643, 5644, 5645, 5646, 5647, 
    5648, 5649, 5650, 5651, 5652, 5653, 
    5654, 5655, 5656, 5657, 5658, 5659, 
    5660, 5661, 5662, 5663, 5664, 5665, 
    5666, 5667, 3137, 1473, 1474
  )

Query time 0.00053

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "100.81"
    },
    "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": 48,
          "rows_produced_per_join": 48,
          "filtered": "100.00",
          "index_condition": "(`gaseus`.`p`.`product_id` in (5623,5624,5625,5626,5627,5628,5629,5630,5631,5632,5633,5634,5635,5636,5637,5638,5639,5640,5641,5642,5643,5644,5645,5646,5647,5648,5649,5650,5651,5652,5653,5654,5655,5656,5657,5658,5659,5660,5661,5662,5663,5664,5665,5666,5667,3137,1473,1474))",
          "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": [
            "gaseus.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": [
            "gaseus.p.group_id"
          ],
          "rows_examined_per_scan": 3,
          "rows_produced_per_join": 144,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "36.00",
            "eval_cost": "14.40",
            "prefix_cost": "100.81",
            "data_read_per_join": "14K"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      }
    ]
  }
}