Best lock deicers and lubricants
I’ve written an article on how to thaw a frozen car door lock here.

Prevent car door lock freezing with an application of dry teflon lube
But the best way to prevent car door lock problems is to keep the lock cylinder lubricated. Use graphite or the newer dry teflon lubes to keep the lock working without attracting dirt and grit.
Posted on by Rick Muscoplat