It's probably fine because of it's high sugar content. (like honey or jam)
Or there is another test, it's called the "24-36 hour test".
Taste some and get back to us in 24 to 36 hours, if you aren't sick, it's fine. Okay, not so funny.
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.