Well, this was interesting because I had no idea there was a convention such as noon or 5 PM, etc. I usually bring the keys and give them to the Buyer at the closing. I once had to take the keys back though, per my attorney's strict instructions, because the loan failed to fund that day. So to follow up on Patti's comment: If you need to get in ASAP, ask your lender if it is possible to fund the loan the night before or first thing in the morning. Some will not do this. But if you ask, you are still likely to get funded a bit quicker than if you don't ask.
Congratulations on your new home!