Sometimes it takes longer to get an app reviewed. Here is an official information:
On average, 50% of apps are reviewed within 24 hours and 90% are reviewed within 48 hours. Some apps, however, may require additional time to review, and there may be times during the year where we experience higher-than-average submission volume and therefore have delayed review times.
For more information, see: https://forums.developer.apple.com/forums/thread/131256
PS: my app is also waiting for a review for almost 24h now.. let's see how long it's gonna take this time
Topic:
App Store Distribution & Marketing
SubTopic:
App Review