Your temps sound fine, and as long as your snake is doing all its little snakey things regularly, there should be no problem. For my python, I personally keep my cool side around 25 Celsius/77 Fahrenheit and warm side around the same as you. It seems like they might prefer a little bit more variety temp-wise, but that's just my opinion.

I don't know what kind of enclosure you're using, but when just using a heat lamp, remember to keep an eye on humidity. It should be between 50-60%. That's one of the big reasons UTHs are recommended over lamps alone, but if that's fine, more power to you.