Highest Speed Data Access

I have inherited a half-finished sql-server based project from a recently departed coworker. The critial point of this project is one app thread that reads barcodes, queries a single table in the database for the one record with that code as its primary key, and makes desisions based on that record. The faster that I can make that go, the better the process will run, up to a max rate as high as 20 queries per second if that were possible. I have a limited
general knowledge of sql, but very little of sql-server express.

My question is what is the best way with sql-server to maximize my single-table request rate?? On some other databases I could create an in-memory temp copy of the table with trigger events on the main table to keep the copy in sync, or I could do an initial select on the entire table to hopefully get the table into cache memory, or I could use some kind of ado-like table on the app side (but do I really gain much of anything doing this??)

With SQL server, what is my best approach to maximize my throughput under these conditions??

FYI..The c++ app uses direct odbc calls to a localhost database. Table theoretically could have 75000 ever-changing records in it. There are 5 or 6 other processes also hitting on this table, but at a far more lakadaisical (say once every 10 seconds level) rate.