I suggested Contact spray as it will dry, some have a very light lubricant to it and if by chance it dose make contact with the electrical it would be an extra bonus.
WD does disperse liquid and the lubricant does evaporate but over time.
Graphite lock lubricant is a solid material that will stay inside but if it gets wet it will clump and then what? Its made for building door,s pad locks and automobile door locks, they sit horizontal or point down (pad lock).
I guess what needs to be done is take a ignition switch apart and see how it's mechanical and electrical components are fitted together.
After all this is on a motorcycle and is made to be in the elements you would think it could take some outdoor abuse, I personalty have seen better keyhole covers on other bikes.
I put a piece of duct tape over it when I wash my bike.