The "Score Card" is located on the upper left corner of the screen below your display picture.
Certain data in the score card is locked. You can unlock the scorecard by spending 70 diamonds. 
Unlocking the score card is a great way to monitor your career progress across each or the MotoGP circuits. Not only will you gain useful information which you can compare against the real race lap times, but unlocking the "score card" will give you access to everyone else's score card.
This is really useful as you can see how your friends are doing on each track and begin to see how people amass the scores they do.
The COMBO is the best driver of score, so having a really high combo is essential to optimizing your score on each track. When you get a PERFECT you will see your combo goes up by 3, so someone who has a really strong track record of getting perfects on a circuit will likely have a really high COMBO and makes very good use of the COMBO Insurance in the Last Chance Performance Boosts.