Looking at the photos, I would say it is a little large. Your snake could likely take it, but it's not worth the risk. Looks like the rats girth is about 3/4 of the width of the pack of smokes, and your snake is about 2/3.
Could the snake safely eat this rat? Yes.
I personally would not feed this size right now, however...if you are going to, I would suggest stunning to rat first.