Food that has *just* gone cold?

I got a pizza from a place about 30 minutes away from my house and now that I have it back it's gone cool. I really don't want to reheat it as I don't have a microwave and putting it in the oven would be a bit of a pain. I ordered it exactly one hour ago so it's been out 45 minutes at the absolute most. Is it still safe? I know the "everything must be steaming hot" rule but if it's JUST gone cold it's okay right?