EDD_DISABLE_REWRITE

This constant allows you to disable the “pretty URLs” for the downloads post type. Some sites, particularly those notusing the downloads post type archive, may want to remove the rewrite structure of the custom post type entirely. This constant allows you to do that.

To disable the rewrite, place this in your functions.php or any custom plugin:

define('EDD_DISABLE_REWRITE', true); 

Note: you will want to resave your permalink structure after doing this.