You could probably contract with an escrow provider at a low fee to do this.
+1
Find someone you trust who will be available at the designated time to send the bitcoin.
Send them the bitcoin payment up front.
Either ask them ahead of time to send the bitcoin at the specified time, or ask them to hold the bitcoin until they receive communication from you (email, txt, phone call, whatever).
Offer them a small token payment in thanks for their assistance.