In prison sometimes the prison guards prevent me from perform- ing Salaat on time.

Answer

In the circumstances you find yourself in prison it is permissible to perform Salaat qadha when the prison guards prevent you from performing it on time. Don't defy them. You will not achieve anything by defiance in your situation. They will only utilize force, brutally oppress and injure you, and prevent you from performing Salaat. You will also adversely affect your parole chances. Prison is a filthy abode for shayaateen. You should not do anything to prolong your stay in such an evil place.