If you know lisp, and have lisp things, and don't have the time for .net, then just do it in lisp. However, think about this in the long run...
As for MySQL, again - i'm not sure what is your experience with database: you have database server, one only, available to all. There you keep your lisp routines, and others connect and download. To do this in .NET there are, again, various ways to do it, one of wich is by having ".NET connector" downloaded from MySQL site, and included in your app. Users will also have to have it, and you can include MySQL connector instalation in your app. However, as I have said it - MySQL connector is GPL code.
Again, if you not sure about MySQL, and all you need is a simple SQL operations, you can download and start some variant of MS SQL server. There was a "compact" or something like that before... check it.