I’d recommend IF EXISTS(SELECT * ...), unless this is actually causing a performance issue. It expresses the intent of the query in a much better understood fashion than alternatives.
I’d avoid COUNT(*) (as in the current answers) unless you actually need the count of rows from the table.
If you want the “efficiency” of checking the rowcount from the result, I’d probably go for:
select 1 where exists(select * from BigTable where SomeColumn=200)
Which produces the same result set as your second query (either 0 or 1 row)