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 (
    1096, 1098, 1095, 1078, 1086, 1099, 886, 
    884, 1055, 1056, 1057, 1058, 786, 789, 
    792, 699, 777, 774, 781, 1024, 1025, 
    1028, 1050, 1051, 1052, 1049, 1067, 
    1033, 1034, 1037, 1035, 1036, 1038, 
    1032, 1062, 1061, 1060, 1063, 1059, 
    1064, 1066, 976, 978, 968, 971, 636, 
    969, 972
  )

Query time 0.00092

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "191.06"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "p",
          "access_type": "ALL",
          "possible_keys": [
            "PRIMARY",
            "idx_group_id"
          ],
          "rows_examined_per_scan": 353,
          "rows_produced_per_join": 48,
          "filtered": "13.88",
          "cost_info": {
            "read_cost": "63.66",
            "eval_cost": "9.80",
            "prefix_cost": "73.46",
            "data_read_per_join": "783"
          },
          "used_columns": [
            "product_id",
            "parent_product_id",
            "group_id"
          ],
          "attached_condition": "(`cscart`.`p`.`product_id` in (1096,1098,1095,1078,1086,1099,886,884,1055,1056,1057,1058,786,789,792,699,777,774,781,1024,1025,1028,1050,1051,1052,1049,1067,1033,1034,1037,1035,1036,1038,1032,1062,1061,1060,1063,1059,1064,1066,976,978,968,971,636,969,972))"
        }
      },
      {
        "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": [
            "cscart.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 48,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "49.00",
            "eval_cost": "9.80",
            "prefix_cost": "132.26",
            "data_read_per_join": "4K"
          },
          "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": [
            "cscart.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 48,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "49.00",
            "eval_cost": "9.80",
            "prefix_cost": "191.06",
            "data_read_per_join": "19K"
          },
          "used_columns": [
            "id",
            "code"
          ]
        }
      }
    ]
  }
}