Can't create index when do MySQL to CUBRID migration

MySQL table definition:

CREATE TABLE `TABLE1` (
`U_NO` bigint(20) NOT NULL AUTO_INCREMENT,
`USER_ID` varchar(20) NOT NULL,
`COL_A` datetime NOT NULL,
`COL_B` varchar(255) NOT NULL,
`phone` varchar(20) NOT NULL,
`COL_C` char(1) NOT NULL DEFAULT 'N',
PRIMARY KEY (`USER_ID`),
UNIQUE KEY `IDX_U_NO` (`U_NO`,`USER_ID`),
KEY `IDX_COL_A_C` (`COL_A`,`COL_C`)
)