I graduated with Master degree in 2011, can i still claim AOC?

No, the AOTC credit is for the first 4 years of college.  Once you have received a degree of any kind from college or university you no longer qualify to receive the AOTC credit.

 

You can possibly claim the Lifetime Learning Credit or take a deductions for Tuition and Fees.

 

The Lifetime Learning Credit is a credit for up to 20% of the first $10,000 paid to attend a university or college when you are working towards a degree.  The credit is limited to $2,000 and you cannot have income greater than

• For TY2019, the amount of your LLC is gradually reduced (phased out) if your MAGI is between $58,000 and $68,000 ($116,000 and $136,000 if you file a joint return).
• You can’t claim the credit if your MAGI is $68,000 or more ($136,000 or more if you file a joint return).

The other possibility is that you can take a deduction of up to $4,000 for Tuition and Fees.

The AOTC is only available for your first 4 year degree or its equivalent, no matter when or where earned.  Since you already have your first 4 year degree, you are no longer eligible even though you never used it in the US.