Do pilots use the pedals in flight on planes with a sidestick (Airbus)?
The rudder pedals are not usually used in flight, even with the autopilot off.
The rudder on the Airbus A320 can be controlled via a mechanical connection to the rudder pedals in the flight deck, but also electrically via the fly-by-wire mechanism. The following graphic shows an overview of the rudder control:

(Airbus A320 FCOM - Flight Controls - Description)
As you can see the sidestick input goes to the ELAC (ELevator Aileron Computer) and from there a Yaw Order is sent to the FAC (Flight Augmentation Computer). This will then be passed on to the rudder via the Yaw Damper Servo Actuator.

Electrical Rudder Control
The yaw damping and turn coordination functions are automatic. The
ELACs compute yaw orders for coordinating turns and damping yaw
oscillations, and transmit them to the FACs.
Mechanical Rudder Control
The pilots can use conventional rudder pedals to control the rudder.

(Airbus A320 FCOM - Flight Controls - Description)
Since the yaw damping and turn coordination are fully automatic, there is usually no need for the pilot to use the rudder pedals in flight.
There are however some situations, where manual rudder input via the pedals is required:

Takeoff Roll: The rudder pedals move both the rudder and the nose wheel steering (NWS, see &quot;NWS ORDER&quot; in graphic above) on the ground to maintain directional control during takeoff and landing. After initiating the takeoff roll, the pilot flying (PF) will use the rudder pedals to control the aircraft:

The PF should use pedals to keep the aircraft straight. The nosewheel steering authority
decreases at a pre-determined rate as the groundspeed increases (no more efficiency at
130 kt) and the rudder becomes more effective.

(Airbus A320 FCTM - Normal Operations - Takeoff)

Landing: When landing the aircraft in a crosswind the direction in which the aircraft points is not aligned with the runway. To align the aircraft before touchdown (called de-crab), the PF needs to apply rudder input via the pedals during the flare:

During the flare, rudder should be applied as required to align the aircraft with the
runway heading. Any tendency to drift downwind should be counteracted by an
appropriate lateral (roll) input on the sidestick.

(Airbus A320 FCTM - Normal Operations - Landing)
This is the only time (for normal operations) where the rudder pedals are actually used in flight.

Engine Failure: After an engine failure the asymmetric thrust of the remaining engine needs to be overcome with the rudder. For an engine failure during the takeoff (but after V1), this needs to be done manually with the rudder pedals:

On the ground: Rudder is used conventionally to maintain the aircraft on the runway centreline. [...]
When safely airborne: [...] Since
the lateral normal law does not command the full needed rudder surface deflection,
the pilot will have to adjust conventionally the rudder pedals to center the beta
target. [...]

(Airbus A320 FCTM - Abnormal Operations - Operating Techniques)
Once the aircraft has accelerated, the rudder is trimmed and no pedal input is required any more.