The German's did have more than 10 divisions on its "eastern front " and remember in 1939-40 these divisions were at full strength -so an infantry division would have over 17,000 men. In addition the germans had fortifications and the ability to reinforce it's position in the east. The German tanks and anti-tank weapons would be very effective against the soviet armor of 1940 as the majority of tanks would be BT5/7, T-26. The Luftwaffe would also be able to help check a soviet thrust to the east. The German's could also count on their Slovkian allies to fight with them at this point.
OK, here I'm assuming that all of the Soviet Cavalry/ Tank divisions have been transferred to the German border, so this puts the Soviet mechanized and motorized strength at (1st April 1940) :
Leningrad MD (1 tank division), Bylorussian MD (2 tank corps and 1 motorized division in Moscow Special District), Kiev MD (2 tank corps), Odessa MD (1 tank corps) and Trans-Baikal MD (1 tank corps).
Each corps consisted of 2 tank divisions, 1 motorized infantry , 1 aviation sqdrn with 12 planes, 1 signal battalion and one motorcycle regiment.
The strength total is quite impressive : 468 T-35s, 7,300 BT-series tanks, 7,985 T-26s, 1,027 OT-26s (flame-tanks), and 3,228 T-38s, not counting the reserve of T-37 and T-38s and the first 243 KV-1s and 85 T-34s.
It's safe to assume that, while the offensive won't topple Germany, it will cause them reeling until at least the German-Polish border, then it will be stymied and the combined Anglo-French-German force will knock them back.