A track on a CD has its length in minutes and seconds stored numerically, and that's the data that's sent to CDDB.

It would be irrelevant if the CD player ran slow or fast, quite apart from the fact that they are crystal controlled and therefore at least as speed accurate as any digital clock that you might test them with.

Now, when you transcribe an LP, the LP player might well not run at the correct speed, and you have a point there.