If you want:
"Excuse me, Mister. Is this taxi available?"
In IDN TL:
"Permisi Pak, apakah taxi ini bisa antar saya?"
I always use this. In Indonesia, we use Mister. Since EN-IDN is very different from EN-US. More likely closer to EN-UK.
Hidden rule in IDN: If you see a man/woman who is 20 -...