So if I'm the person who will be interviewing you, am I going to be going into this interview with the expectation that you already have these certifications?
If i'm not expecting you to already have these certifications, if I ask about them all you have to do is tell me that you're working on them and expect to have them by whenever. I'll accept that response and we'll find something else to talk about.
If I am expecting you to have these certifications, it's because you told me in some form that you had them. Maybe you put it on your resume or application, or maybe it was you deciding to apply for a job that clearly listed these certifications as requirements. Regardless, I'm expecting you to have them, so if you then tell me that you don't, that's not going to go over very well. Instead of coming up with different questions, I'll be ending the interview.
If the entire point of the interview is to ask you about these certifications, it's very unlikely I agreed to interview you without having the expectation that you've already got these certifications.