Extended syntax so that it is possible to set innodb_lock_wait_timeout and
lock_wait_timeout for the following statements:

Syntax
------

ALTER TABLE tbl_name [WAIT n|NOWAIT] ...
CREATE ... INDEX ON tbl_name (index_col_name, ...) [WAIT n|NOWAIT] ...
DROP INDEX ... [WAIT n|NOWAIT]
DROP TABLE tbl_name [WAIT n|NOWAIT] ...
LOCK TABLE ... [WAIT n|NOWAIT]
OPTIMIZE TABLE tbl_name [WAIT n|NOWAIT]
RENAME TABLE tbl_name [WAIT n|NOWAIT] ...
SELECT ... FOR UPDATE [WAIT n|NOWAIT]
SELECT ... LOCK IN SHARE MODE [WAIT n|NOWAIT]
TRUNCATE TABLE tbl_name [WAIT n|NOWAIT]

Description
-----------

The lock wait timeout can be explicitly set in the statement by using either
WAIT n (to set the wait in seconds) or NOWAIT, in which case the statement
will immediately fail if the lock cannot be obtained. WAIT 0 is equivalent to
NOWAIT.

URL: https://mariadb.com/kb/en/wait-and-nowait/