Do green lentils go bad?
If you are talking about dried uncooked green lentils, then they are probably good for another 4 or 5 months depending on the condition they were stored in and how they look now.

Dried lentils are safe to use after the "expiration" date on the package, provided it is properly stored and the package is undamaged - commercially packaged dried lentils will typically carry a " Best By," "Best if Used By," "Best Before", or "Best When Used By" date but this is not a safety date, it is the manufacturer's estimate of how long the dried lentils will remain at peak quality.

If there are no Weevils or any srot of bugs and you do not see any spoilage you are good to eat them.