First I wouldn't ask someone out I didn't know through a fast food drive-thru, esp if they are not gay, and esp at a workplace. Maybe you can go there during the week, often or once a week and start up a conversation with him, joke around with him or spark some kind of conversation. Maybe order something without the usual toppings, so you have more time to talk with him, as you wait. Maybe give him a note the next time you order and ask him out that way, perhaps ask him to a movie, or dinner,and jot down a time and a place to meet if he is interested, and see what happens. Just remember not everyone is gay, or accepts homosexuality, so be careful when approaching ppl you don't know. Good Luck.