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 (
    20775, 16163, 14142, 16150, 20824, 20773, 
    20809, 20789, 14214, 14229, 20778, 
    14262, 14194, 20735, 14212, 14216, 
    14237, 14177, 20793, 14164, 14172, 
    20790, 14238, 32164, 14158, 14225, 
    14263, 14204, 14154, 20758, 21008, 
    20801, 20882, 20745, 14221, 20929, 
    21068, 20932, 20812, 20852, 20725, 
    14206, 14191, 20823, 20923, 20797, 
    20802, 20884, 20853, 20815
  )

Query time 0.00136

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "71.16"
    },
    "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": 51,
          "rows_produced_per_join": 51,
          "filtered": "100.00",
          "index_condition": "(`cscartdb`.`p`.`product_id` in (20775,16163,14142,16150,20824,20773,20809,20789,14214,14229,20778,14262,14194,20735,14212,14216,14237,14177,20793,14164,14172,20790,14238,32164,14158,14225,14263,14204,14154,20758,21008,20801,20882,20745,14221,20929,21068,20932,20812,20852,20725,14206,14191,20823,20923,20797,20802,20884,20853,20815))",
          "cost_info": {
            "read_cost": "30.36",
            "eval_cost": "5.10",
            "prefix_cost": "35.46",
            "data_read_per_join": "816"
          },
          "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": [
            "cscartdb.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 51,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "12.75",
            "eval_cost": "5.10",
            "prefix_cost": "53.31",
            "data_read_per_join": "19K"
          },
          "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": [
            "cscartdb.p.group_id"
          ],
          "rows_examined_per_scan": 1,
          "rows_produced_per_join": 51,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "12.75",
            "eval_cost": "5.10",
            "prefix_cost": "71.16",
            "data_read_per_join": "5K"
          },
          "used_columns": [
            "feature_id",
            "purpose",
            "group_id"
          ]
        }
      }
    ]
  }
}