I can't find time zone tables in sys database of MySQL
I used to face the same issue as you and I resolved it by following these quick steps.

Please follow below:

Environment:


MySQL Version: 5.7
OS: Windows 10 (64 bit)


Steps:


Download the package that contains the data files of pre-built time zone tables. You can download here https://dev.mysql.com/downloads/timezones.html 


timezone_2018e_posix_sql.zip - POSIX standard for MySQL version 5.7

Extract the downloaded package, you will then have a file named timezone_posix.sql
Open a command line in the root directory of MySQL. Ex: On my
computer this is "C:\Program Files\MySQL\MySQL Server 5.7\bin"
Run the command mysql -u root -p to login to MySQL with root access and then enter password.
Run the command show databases; to view all database. You will see a database named mysql. You need to insert data into the mysql database


Run the command use mysql;

Finally, you can insert data by issuing the command source *path timezone_posix.sql*.


After inserting the timezone data, you can test by issuing the following query:

 SELECT CONVERT_TZ('2018-07-02 14:46:46','utc','America/Los_Angeles')


If the result is not null, you're successful!!!