How many columns are in this "large" table?
SELECT * (2 or 3 columns) FROM TABLE will run quite well most of the time, whereas if you have dozens of columns in that table, it will take quite some time to pull in the information as you'll be scanning the clustered index (assuming the table has one)
Without seeing the DDL or an execution plan, it's difficult to tell where your issue is...could be a matter or just tweaking a few included columns in an existing non-clustered index (assuming these exist as well)
Do you really need all columns to be returned?
Never argue with an idiot; Theyll drag you down to their level and beat you with experience