It depends on your model. Most of the laser printers have a power save mode. After 15-30 minutes it goes into standby mode (similar to monitors) and consumes only 3-10W of power. As a downside, after resuming, they do need a minute or two to warm up the fuser and print.
Many of the latest models do even better - they have 'instant on' fuser tech. The fuser and consequently power consumption increases to 250-300W only when printing, and can immediately print - in 15-20 seconds. Such models may always remain in a 'standby' mode, consuming 3-10W of power.
There is no question of consuming ink or toner. These are consumed only when printing.