Inside the temple, I found a circular room with six balconies, each one with a serpent statue on the edge. Curious, I pushed one of them to see what would happen, and it was a trap! I nearly fell to my death from the explosion. Laying [sic] there on the ledge, I looked down and noticed that there was another statue at the base of the room; an altar of sorts... Hakkar, I think it was called.
I think that this altar is the secret -- you must bring this token to the altar in the Sunken Temple.
The altar you are looking for is at the bottom of the Sunken Temple. You'll most likely need to clear out the area of creatures before you can click on the altar.