OTOH - if this battery was installed in 2015 as ordsgt suggests, it's time to think seriously about replacement. In my experience a flooded cell car battery's life, no matter how much you pay for it initially (remember Sears "Die Hard"?), and especially if it has not been driven and kept charged regularly, is no more than about five years. That swelling and cracking around the post does not look healthy to me. I don't necessarily replace at five years but if it goes dead for no reason I'll charge it once then when it goes dead again, it's gone. I just last week replaced a battery that was from July 2016 (7-1/2 years), it went dead two weeks after I last drove the car. It could not even be jumped.
I agree that the corrosion on the terminal and underneath the hold down is normal and nothing to be concerned about. But the swelling and cracking around the post, and the age, would concern me.
I don't have any experience with life of AGM batteries like the Optima in cars. I did have an Optima battery in my last touring motorcycle and it was going strong at seven years.