Superficial surface finish cracks are prone to all guitars. Importantly, more in used guitars. Strats tend to crack the paint or finish surface in that exact same spot where the neck meets the body. Used guitars are especially more prone as they have been handled more. If you bought a used guitars that was not listed as Mint, NEW or Perfect then it's used. Ordinary wear and tear and surface cracks are to be expected sometimes, so clearly a surface crack in the body where the neck meets the pocket is a non-issue. Equally important, if a used guitar plays well and sounds good and is in excellent playing condition why worry? Remember-most used guitars aren't beauty pageant entries, just good playing guitars. You have to ask yourself? Did I buy the guitar to play it or look at it? When you said nothing about how well it plays but just how it looks it's not the guitar with a problem.