Didn't they find old honey in the pyramids?.....lol, I think honey is almost always good....perhaps even the older the better. I've never seen green growth on honey, and have eaten a lot of it in my 64 years. I also use it as an antiseptic treatment on cuts. It's great for splinter removals too. Whenever I get a splinter (hey, I live in a wood hut on a beaver pond, so...splinters a-plenty).....I put a gob of honey onto it, cover it with a bandaid overnight. By next morning, the healing is almost done.....splinter falls out and never any sign of infection, even if there was some to begin with. I consider honey a miracle healer.
Good luck with yours. I'd just heat it up in the microwave; it should melt up nicely.