should be fine.

these re-useable hand warmers are awesome for situations like this. You can store them for years, they deliver heat quickly when you trigger them, and after use you just reset them to their original state by putting them in boiling water until the crystals are completely dissolved. Just good to have, can help with power outages, or with transport situations, or with a rescue when you take in one more animal than you can provide heating for and need to bridge a day or two.

but dont worry too much, cold temperatures dont kill quickly, snakes can survive that for quite a while.