There is no indication of past present or future time in the original Greek. I found the text in Greek and English at this biblehub page. As you can see, it simply shows there is a relationship, not the exact nature of it. The first Greek text is from the SBLGNT version, which closely matches the Greek text used by the NIV translators, also found on bibehub.
(Luke 3:38 [SBLGNT])
τοῦ Ἐνὼς τοῦ Σὴθ τοῦ Ἀδὰμ τοῦ θεοῦ.
GRK: ... Σήθ τοῦ Ἀδάμ τοῦ θεοῦ
NAS: ... the son of Seth, the son of Adam, the son of God.
KJV: ... which was [the son] of Seth, which was [the son] of Adam, which was [the son] of God.
INT: ... of Seth of Adam of God
The INT (interlinear) line is the key to what is in the Greek text. The word "τοῦ", transliterated to "ton", is a form of the Greek for "the" and here is understood to mean "of".
Both the KJV and NAS add the words "the son" to clarify the relationship for the English reader. Only the KJV chose to add "which was", which suggests, but does not require, that the relationship no longer exists.
Another way to put it could be, " ... Enos came from Seth came from Adam came from God". And then I wonder if I should add some "who"s in there.