There were probably professions that long predate history, and any of those are a bit hard to prove. There were 'shaman' in pre-history, and good shaman were quite possibly supported by their communities. There may also have been things like dedicated cooks. Trading sex for food however, is clearly hundreds of thousands if not millions of years old, so it's hard to argue that other professions came before it.
I'm imagining dinosaur hookers, out on the jungle corner in fishnets and halter tops, smoking cigarettes and shaking their tails at passersby.
Edit: look at that second word before anyone gets snarky about dinos and humans not coexisting. We can have fun that ignores reality, and there's nothing more fun than picking up a t-rex hooker in your Flintstonesmobile, taking her back to your cave and smoking some rock. It's a gneiss day.