2 outer so the implied pot would have to be >$63 to call $2.80.

2/47 = 0.0425531915 (4.3% chance to make an out)
((1/0.0425531915)*2.80)-2.80) = 63

So as long as the pot's about 22.5 times as big as the flop bet by the river, calling seems to be a good play. Although...had a third spade come on the river you might have lost. So perhaps the number needs to be larger to account for the times you make your set and lose. Maybe guesstimated pot size of >25x the flop bet would be better.

What do you put supertv on, AsKs/AsXs?

Disclaimer: I'm a newb that knows very little but I think I got the math right.