Anil - journals don't generally work by minimum times. They may state an 'average' review turnaround - but how that turns out is highly variable depending on many factors. My suggestion for quick turnaround - is not actually the review process. many reputable and popular journals now go through an initial editor screening process, before sending out to formal review. These journals often state this in their author instructions. Where this occurs, it is usually no more than a week or two to get a response - and can be a big time-saver.
There isn't really a minimum time. It all depends on various factors such as the journal and availability of reviewers . From my personal experience thus far it has taken as little as one month to as much as 3.5 months.