There is no single sensor, at least as far as I’m aware, that provides an output measured in Watts or Joules. You will need to combine a current sensor of some kind and a method to determine your line voltage.
As for your other question, a current sensor like ACS723 uses the Hall effect to measure current using magnetic fields and is galvanically isolated from the rest of the circuit. The sensor’s isolation is rated for a working voltage of 297V (rms) so it would be fine for 220V line voltage. Sparkfun notes that their breakout board for the ACS723 isn’t designed to handle the IC’s maximum isolation of 2.4kV, but they don’t say what their actual max is. I would assume it’s okay for 220V though.
In general, a current sensor doesn’t care about voltage because that’s not what you’re putting into the device.