Insert one data to MySQL table without login

You can use the same command, but after adding the DB name like:

$ mysql -u root -p db1 -e "your-insert-here"

You can just add a use db1 command to the string you pass to mysql.

mysql -u root -pz -e "USE db1; INSERT INTO role_permissions values (1,'create about_us content','node');"

Also, did you create your role_permissions table e.g.

mysql -u root -pz -e "USE db1; CREATE TABLE role_permissions (id INT, data VARCHAR(200), type VARCHAR (10);"