Well, in those times Russia was pretty busy with its own mess.
Yes and no. On the other hand in 90's they still had a huge army. These days they went for "more modern", "professional" etc. western style "quick reaction forces" which are good in local conflicts but are not really capable of massive invasion. They would need many, many months to get ready for that, call up reservists etc. and even If our army fall down like a house of cards, they would be struggling to hold the territory of that size and population.
Anyway, these are just "technical" issues, Russia is not a direct military threat to Poland. Attack on Poland might happen only as a part of far larger conflict and don't tell me you seriously believe that Germany or America will risk war with Russia because some piece of paper says so. If things go bad on the grand scale, each and every country will start calculating what to do and make decisions based on their national interests.
Instead Russia might use various "asymmetric" methods, like cybernetic warfare etc. What EU is going to do then ? Or cause trade related problems. Some years ago they banned our export of meat. Normally we would just rise tariffs to the sky on anything coming from Russia, control 20 times each truck that carry Russian imports/exports, so they would quickly re-think that decision. But being in EU we couldn't do that, that would have been against "EU policies". So Poland had to complain to EU's HQ, EUnuchs were "investigating" for long enough to have the Polish companies replaced on that market by... Dutch, German, Austrian etc. So much of "EU helping with Russia" :)))
I'm not pro-Russian whatsoever, we know them too well. But apparently the west is doing the business with Russia (Gerries, Dutch, French etc. just struck another gas deal with Russia, so much for the sanctions :))) and at the same time use Russia as a boogeyman to drive "further integration" in "Eastern Europe". That was used as one of "pros" in case of Balts' (who unlike Poland could be easily conquered by Russia before anyone really notice) anschluss to the Euro Area. Now tell me, If Russian Air Force tomorrow violate the air space of Estonia, what's going to happen ? Mario Draghi will release a strongly worded statement ? Let's be honest, not even that :)))