I'm not sure what translation you used here, but the most accurate translations say:
King James: Joh 18:36 Jesus answered, My kingdom is not of this world: if my kingdom were of this world, then would my servants fight, that I should not be delivered to the Jews: but now is my kingdom not from hence.
Literal interpretation (Greenes') Jesus answered, My kingdom is not of this world. If My kingdom were of this world, My servants would have fought that I might not be delivered up to the Jews. But now My kingdom is not from here.
The word translated "now" is the greek "nun"...Thayer's Lexicon defines it as "at this time, the present, now".
So he's saying "....at the present time my kingdom is not of this world."
The concept is that the Jews expected a conquering messiah, a king to crush Rome. Pilate was trying to find out if this was true...if he was the man. Christ was telling him "I'm a king, but I'm not here to have a physical kingdom...yet."
I use the ESV, which I’ll take for accuracy over the KJV...
NASB has it: Jesus answered, “My kingdom is not of this world. If My kingdom were of this world, then My servants would be fighting so that I would not be handed over to the Jews; but as it is, My kingdom is not of this realm.”
Notice he does not say, “My kingdom is not of this time. If my kingdom were of this time...”
That is why the translators don’t use time (hence)...it can also refer to place, and Jesus is using place earlier in the sentence.