I'm not sure it is a key. All of the vintage iron keys I've seen of that size have been 'skeleton type' keys. I'm not saying it's not a key, but judging by it's size via the pork 'n bean spoon (lol), it doesn't look like an iron key.
It resembles the side portion of a vintage mortise door lock.
Can you post a pic of the broken end? Also, use a medium colored background like blue or green instead of white because the item will photograph better.
Oh, okay, I see that it is a whole piece now. From the first pics, it look like part of it was broken off. How thick is it? Does it look like it's too thick to be a key?
Sorry about that first set of pics :\ but it seems to be a usable key its solid no holes for a ring has some good weight to it makes me feel like some type of security key like a vault or jail just something secure