運命と想いは時空(とき)を越えて
Transliteration: Unmei to omoi wa toki wo koete
Translation: Fate and love transcend time and space
時空 translates as “space-time” or “space and time.” The on-yomi or Chinese reading of these kanji are jikū.
However, it’s read and sung as toki, the kun-yomi or Japanese reading of the kanji 時.
If you’re listening to the song and you hear toki, you may just imagine 時.
Reading the lyrics 時空(とき)adds another layer of meaning. Now we’re talking about space too. Aw, snap!
Why do lyrics have kanji readings like this?
There’s no one answer. It’s the creative choice of the person who wrote the lyrics! This is also common in Manga.
In Anime too, you’ll most likely see the lyrics onscreen.