First, break the large wooden block on the lowered side of the middle scale - using the nearby torch to light an arrow and burn the box, and it will rise that side, bringing down the other side where you will find a key. When you enter the Qua Raym Shrine, you will find yourself faced with a large balance scale in the middle of the room, a locked door across the room, and another balance scale at the left end of the room from the door that's a bit higher up on the wall.
