At the beginning of your script, just after connection to MySQL, execute this query:
SET SESSION time_zone = 'Asia/Kolkata';
Documentation: MySQL Server Time Zone Support
if you get an error when executing the query:
ERROR 1298 (HY000): Unknown or incorrect time zone: 'Asia/Kolkata'
then it means the timezone data is not loaded in your MySQL server. You may do so by following the explanations given in the chapter Populating the Time Zone Tables or you may try using numerical values instead of named timezones:
SET SESSION time_zone = "+5:30";