As I understand it, it would be better to keep the entire text file in your MySQL DB for a couple of reasons.
First, you get more options if you have to search the data if it is stored in a MySQL table.
Secondly, the MySQL server will take the (albiet small) processing hit rather then your web server. On low load systems, this isn't usually a problem but if you get some heavy traffic, you might want to alleviate the load slightly on the web server. On a small text file, I doubt this will matter much, though.
-Ben