I used it just last week. I was only asked for my AmEx card even though I came prepared with my receipt showing I'd purchased passes online.
It is an unassuming entrance with a small placard that just says American Express Lounge (it's across from the gift shop for Shrek 4D). Inside is a small lounge area with several chairs and couple of tables. There is a beverage cooler that contained small bottles of water, a basket holding potato chips, and a basket holding granola bars. It has good AC, and was a nice spot to just chill for a little while. There is also a bathroom available. We enjoyed having a spot away from the heat with free snacks and water.
HTH!