The question is really "Did Russia expand to the Sea or was it constrained by the sea?"
Russia has had a piece of the Black Sea coastline since around 1600. They had Murmansk and the Baltic since the 1500s, Siberia and its Arctic and Pacific coasts since the early-mid 1700s. At its peak it had actually crossed the Bering Strait and had colonies as far down the North American Pacific Coast as Ft. Ross (about 200 miles north of today's San Francisco). Since then it as withdrawn completely from North America and has not made any real move toward the India Ocean or the Med.
The "warm water port" theory dates back to the British Empire. England was, quite correctly, in constant fear of losing the Raj. Without the subcontinent's wealth and dominant military position, Great Britain's Empire would have been a small "e" not a capital "E". The French, Russian, even the Dutch & Portuguese ALL wanted it and British policy was built around denying it to all comers until after the Second World War. Of all the contenders, Russia was, on paper, the most severe threat. All the other players had to defeat the Royal Navy to get at the Raj, something the the British dealt with by having a fleet double the size of any alliance that might spring up and ensuring that its fleet was always the best worked up of all the big contenders. Russia, however, could move overland with an army so large that the Empire's forces could not hope to match. Hence the "warm water port" obsession by London. St. Petersburg and Moscow followed the British line of reasoning and then also became obsessed, not that they could ever have achieved their goals.
In modern times The Russians/USSR have never made any serious attempt to reach either the Med or Indian Ocean. Afghanistan was feared by some Western observers to be a lunge for the Persian Gulf; in fact it was a matter of keeping the right bunch of bastards in power in a neighboring country, one that went VERY wrong.
By far Russia's best hope of reaching the Med was during WW I. The Ottomans were weak, the British and French were busy with the Germans (and for one of the very rare historical periods were the Russians allies) and the Czar had that huge army ready to go. Unfortunately, the huge army was, as it had generally been, a paper tiger. Any Russian thought of moving in the direction of the Med died at German hands.
Today, there is no hope of reaching the Med, Gulf, or Indian Ocean without engaging in an utterly unwinnable war. Moreover, the reason for getting such access is effectively gone. With the current transport net and the ready availability of air travel the even theoretical need to push out to any of the remaining major sea lanes is noneexistent.