The warm key is obtained from a chest in the Smoke Dungeon. Player must light all four torches in the corners of dungeon, and then search the chest in the centre of the dungeon to obtain the key. It will have to be picked up before one of the torches goes out. You do not need ice gloves to pick up the key, but it's recommended that you wear ice gloves while fighting Fareed.
The key is used to open the gate to fight Fareed in the Desert Treasurequest. The key is unobtainable after opening the gate. Attempts to re-obtain the key will result in the player receiving the message "There is nothing inside the chest." and all of the lamps used to open the chest cannot be relit.
The key can be kept if you leave the dungeon, so low levels could do two trips, to restock before the fight.
After the quest, Fareed's room can be entered without the key.