How to avoid MySQL Hiccups?

Well, I recently used the MySQL DLL for login servers in my game, my problem is I need to remove all database connection from the clients, instead, they'll send all their data to my server and my server will make the DataBase connection and send them back info. But my problem is every query causes a Hiccup which is a small waiting time, so what if 30 players send data, while other 5 players are playing? It'll have to Queue the 30 queries, wait for them to complete and then continue processing normally. How can I avoid this hiccups and process queries meanwhile processing other code? PS. Bandwidth is no problem.