It differs from person to person. Last year, our k-1 petition was approved beginning of April, received in Cairo end of April. The packet was received mid May. We turned it in mid June, got it returned due to a clerical error and because I write very persuasive emails, we got an interview 2 weeks later. However, after the interview, we were put on AP/AR. Most ME/NA men have some sort of administrative processing following their interview. We received the visa 1.5 months later.
Howeva, more recently, there have been longer waits for interviews and longer AP/AR times. As with everything in immigration, hope for the best, plan for the worst. If your file was just received in Cairo, you could be looking at 2 months to 8+ plus for everything to be over with.