In MySQL and MariaDB, utf8 is not actually UTF-8 encoding. Always use utf8mb4.
To convert a table to utf8mb4:
ALTER TABLE `table_name` CONVERT TO CHARACTER SET utf8mb4 COLLATE utf8mb4_unicode_ci;
To show character set and collation variables:
SHOW VARIABLES WHERE Variable_name LIKE '%collat%' OR Variable_name LIKE '%character%'