According to Official Guinness Records,
The fastest time to solve a 5x5x5 Rubik’s Cube is 37.93 seconds, achieved by Feliks Zemdegs (Australia) at the Canberra Autumn 2018 competition in Canberra, Australia, on 22 April 2018. Feliks broke his previous record of 41.27 seconds to achieve this feat.
For a complete list of 2018 records, please visit 2018 Guinness Records in Australia.