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 (
    6903, 6911, 6993, 7438, 7415, 7422, 7439, 
    7443, 6880, 6996, 9523, 7172, 9520, 
    8132, 8133, 9372, 9413, 9521, 9522, 
    9368, 9374, 9375, 9624, 8793, 9414, 
    9415, 9419, 9420, 9426, 9427, 9524, 
    9416, 9417, 9418, 9469, 8791, 8794, 
    9373, 8413, 8790, 8792
  )

Query time 0.00082

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "57.41"
    },
    "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": 41,
          "rows_produced_per_join": 41,
          "filtered": "100.00",
          "index_condition": "(`softwarepirmam_hewadelivard_cscart_4`.`p`.`product_id` in (6903,6911,6993,7438,7415,7422,7439,7443,6880,6996,9523,7172,9520,8132,8133,9372,9413,9521,9522,9368,9374,9375,9624,8793,9414,9415,9419,9420,9426,9427,9524,9416,9417,9418,9469,8791,8794,9373,8413,8790,8792))",
          "cost_info": {
            "read_cost": "24.61",
            "eval_cost": "4.10",
            "prefix_cost": "28.71",
            "data_read_per_join": "656"
          },
          "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": [
            "softwarepirmam_hewadelivard_cscart_4.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 41,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "10.25",
            "eval_cost": "4.10",
            "prefix_cost": "43.06",
            "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": [
            "softwarepirmam_hewadelivard_cscart_4.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 41,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "10.25",
            "eval_cost": "4.10",
            "prefix_cost": "57.41",
            "data_read_per_join": "4K"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      }
    ]
  }
}