To download karaoke arrangements without the background visuals, you can go to https://karaoke.stingray.com/store/singingmachine/browse/featured/nil/all and log in with the same account you use for the karaoke app. Then, in My Account, you can select Change File Format and then select the ZIP (MP3+G) option.

This will allow you to buy and download the music with the lyrics without background visuals. 

The downloads will have two file, a mp3 and a CDG file. The CDG file will contain the lyrics.

This is the library view from the store website:

If later you want the backgrounds, simply change the file format in My Account to one of the MP4 options.