MySQL 8.0

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CREATE TABLE test
    (`ele` varchar(3), `dim1` varchar(3), `dim2` varchar(3), `dim3` varchar(3))
INSERT INTO test
    (`ele`, `dim1`, `dim2`, `dim3`)
VALUES
    (123, '*', '*', '*'),
    (123, 'DM1', '*', '*'),
    ('abc', '*', 'DM2', '*')
SELECT *
FROM test
WHERE ele = 123 AND
      (dim1 = 'DM1' OR dim1 = '*') AND
      (dim2 = 'DM2' OR dim2 = '*') AND
      (dim3 = 'DM3' OR dim3 = '*')
ORDER BY (dim1 = '*') + (dim2 = '*') + (dim3 = '*') ASC
LIMIT 1


ele
dim1
dim2
dim3


123
DM1
*
*