Learn English – What does “blue corn moon” mean in this song

Racket as in protection racket (organized crime). Here it is used jokingly to mean any sort of business or activity. I guess it's a kind of synecdoche and it probably originated in the US in 1930's.

It's a fairly uncommon expression these days, but "blue" is probably referring to your face turning blue when holding your breath or when you are unable to breathe, so he's basically saying he wants love with enough force that it's as if he can't breathe because of it.