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 (
    976, 978, 968, 971, 636, 969, 972, 977, 
    1022, 1023, 1106, 1110, 1131, 1142, 
    1157, 1159, 1013, 1105, 1108, 1152, 
    1153, 1154, 1120, 1101, 1104, 1111, 
    1134, 1140, 1141, 979, 989, 632, 613, 
    617, 621, 622, 1015, 1016, 1018, 1019, 
    611, 612, 980, 1007, 1002, 638, 997, 
    990
  )

Query time 0.00064

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "196.32"
    },
    "nested_loop": [
      {
        "table": {
          "table_name": "p",
          "access_type": "ALL",
          "possible_keys": [
            "PRIMARY",
            "idx_group_id"
          ],
          "rows_examined_per_scan": 379,
          "rows_produced_per_join": 49,
          "filtered": "12.93",
          "cost_info": {
            "read_cost": "68.93",
            "eval_cost": "9.80",
            "prefix_cost": "78.73",
            "data_read_per_join": "784"
          },
          "used_columns": [
            "product_id",
            "parent_product_id",
            "group_id"
          ],
          "attached_condition": "(`cscart`.`p`.`product_id` in (976,978,968,971,636,969,972,977,1022,1023,1106,1110,1131,1142,1157,1159,1013,1105,1108,1152,1153,1154,1120,1101,1104,1111,1134,1140,1141,979,989,632,613,617,621,622,1015,1016,1018,1019,611,612,980,1007,1002,638,997,990))"
        }
      },
      {
        "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": 49,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "49.00",
            "eval_cost": "9.80",
            "prefix_cost": "137.53",
            "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": 49,
          "filtered": "100.00",
          "cost_info": {
            "read_cost": "49.00",
            "eval_cost": "9.80",
            "prefix_cost": "196.33",
            "data_read_per_join": "19K"
          },
          "used_columns": [
            "id",
            "code"
          ]
        }
      }
    ]
  }
}