It is best if you answer this question clearly and concisely. Be upfront about what you can and cannot do. Avoid committing to hours that will put too much pressure on your personal life. It's always best to frame your response in a positive way. So, rather than telling the interviewer what you cannot do, focus your answer on what you can do.
"I am looking for full-time employment and prefer working daytime or afternoon shifts. I have a young family that I would like to spend my evenings with as often as possible. Of course, should you be in a pinch and need evening coverage now and then, I am certainly willing to be a team player. Do my hours of availability meet your current needs?"
"I would like to offer a range of availability as I kick-start my career in security. I know this may mean night shifts, doubles, shift work, and even weekends and holidays; however, I am prepared to start where I can!"