Connecting Sharp GP2Y1010AU0 (5V) to ESP8266 (3.3V) - pin nr 3 - do I need transistor?
You don't have a voltage problem there -- you're feeding the base of a BJT which is a current-mode device, and the pull-up resistor on that line is connected to V-LED, which is also at VCC (3.3V) here. The way they've designed that part, the LED circuit can run on a completely independent power supply.

EDIT: I confused VLED with the base input. You should be fine to run GPIO13 straight to Pin 3, there's no need to source additional current because the LED current is sourced from Pin 1.