locks on storage spaces won't open

[MikeMarie]

It has been a couple of years since I tried to open the storage spaces (basement) on my Melbourne and when I tried to turn the key it will not turn. Hence, I can't open the panel. I suspect that it has rusted over the past couple of years. Any ideas how to unseal the lock? I don't want to break the key and will no doubt have to buy new locks but first I have to be able to open the panel.

 

[LCBoyer]

Try spraying some WD-40 into the key hole. Insert key and remove, spray again. Wait a few minutes. Try to turn key