Selecting row from a table

Hi All

I have a table with nearly 10,000 rows and 50 columns.

I have a select query like
select * from tablex where col1=5 and col2='a'

I run this from my java program using jdbc.
All I am interested is if there is match or not.

Is there a better way to write the query instead of saying "select *"
I am thinking select * might take more time.

Please let me know.

Thanks