The title is a mix of Russian and Azerbaijani/Turkic slang:
"Ay" is a common Azerbaijani/Turkish calling particle (like "Hey" or "Oh"), and "Brat" is the Russian word for "Brother," used colloquially as "dude" or "mate."
The phrase translates roughly to "While you're young, hey brother," often implying a theme of living life to the fullest or seizing the moment while youth lasts.
It is particularly popular in Azerbaijan and among the Russian-speaking diaspora in Central Asia and the Caucasus.
The inclusion of "Yukle" in search queries points to a high demand for the song on MP3 hosting sites and YouTube converters. This is common for regional hits that may not be as easily accessible on Western-centric platforms like Spotify or Apple Music, leading fans to use direct download services.
Russian for "While [you are] young."