If there is no offer to fill your order it will stay open until someone offers the price you set the order to. If you want a fast completed order cancel the old one and open a new one at 295 or whatever the price is right now.
What do you mean fast ? How long it takes ?
if you are selling or buying KHS it should be based on the current market price in scrypt.cc
lets say current selling price is 295, you cant sell your KHS at 350, no one will buy that for now since someone is still selling at 295, 296 or 294
same with buying KHS, if you plan to buy KHS, and current buying price is 294 dont put a price tag of 250, you have to wait for the market price to go down to 250 before someone sells their KHS at your desired price