Resin does have a shelf life but many variables will affect it, temp, sunlight, humidity, storage container. What has a shorter shelf life is the Catalyst, the MEKP.
Usually after a few years the resin will start to gel, then it is no good to use.

If it is unopened and stored in a cool ,dark place and sounds like it did when you purchased it, you probably could use it, but test a small batch first before use to see if it will catalyze correctly.