In a B150 chipset, there's very little difference between an i5 6600K and the less expensive i5 6600, other than that the latter comes with a cooler and the "K" CPU does not.
You can use it but with B150 chipset you are stuck with stock clocks/No overclock.
To truly use that CPU to its potential you will need a Z170/Z270 motherboard.
In a B150 chipset, there's very little difference between an i5 6600K and the less expensive i5 6600, other than that the latter comes with a cooler and the "K" CPU does not.