There are 2 reasons, and a combination of these 3 probably happened.
1. EVs. Your Cinderace was probably not EV trained in Speed, while the Golurk was. This alone doesn't get the Golurk faster though.
2. Natures- Natures have a big impact on a stat. They increase a stat by 10% and lower one by 10%, if it isn't a neutral nature. The Golurk probably had a Speed boosting nature like Jolly, and yours didn't, maybe it even has a Speed reducing nature like Quiet. However, both of these don't make The Golurk faster. That only leaves one thing.
3. Choice Scarf. The Golurk probably had a Choice Scarf, this boosts your speed by 1.5x. All of these things combined would make your Golurk faster.
Hope I helped!