It is a hymn, not the Bible, which says “and time shall be no more.” Revelation 8:1 speaks of “silence in heaven for about half an hour.” Even the presence of music in heaven implies some sort of time duration, since meter, tempo and rests, which are intrinsic to music, are all time-related. (What is a half note or a quarter note without time?)
2 Peter 3:8 says, “With the Lord [it does not say “with believers in heaven”] a day is like a thousand years, and a thousand years are like a day.” This is rooted in the fact of God’s infinity—He exists outside of time and space, but there is no indication his creatures do.
Whether there is time in heaven or not, heaven clearly enters into the sequences on earth, right down to inhabitants rejoicing over conversions on earth (Luke 15:7) and martyrs looking for and anticipating judgments on earth (Rev. 6:9-11). The book of Revelation shows a continuous interaction of heaven with sequential events happening on earth. (This contradicts the notion that those in heaven are disconnected from or disinterested in what happens on earth.)
For more information on the subject of Heaven, see Randy Alcorn’s book Heaven.