MyISAM doctrine:schema:update error

[mydoctool]

In test env I use MyISAM tables (for best performance).

After the command "php bin/console doctrine:schema:update -f --nv=test" I have error

` An exception occurred while executing 'CREATE TABLE lexik_trans_unit (id INT AUTO_INCREMENT NOT NULL, key_name VARCHAR(255) NOT NULL, domain VARCHAR(255) NOT NULL, created_at DATETIME DEFAULT NULL, updated_at DATETIME DEFAU
LT NULL, UNIQUE INDEX key_domain_idx (key_name, domain), PRIMARY KEY(id)) DEFAULT CHARACTER SET utf8 COLLATE utf8_general_ci ENGINE = MyISAM':

SQLSTATE[42000]: Syntax error or access violation: 1071 Specified key was too long; max key length is 1000 bytes `

Symfony 3.4.14
php 7.2
mysql 5.6