Molasses is one of those foods that seem to last for nearly forever (like honey and fish sauce). I've had some that was over 10-years old that was perfectly fine. Being crystalized does not mean it's bad - just old.
It's bad if it has mold growing on it ....
"It ain't what you don't know that gets you in trouble. It's what you know for sure that just ain't so." - Mark Twain