SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '68260e08e7ba9fd2105edfcb77ccd166e1532fccd9ae0caed902916000fbda66' 
  AND token = 'hqCg0BcCglRQLcZYJL47xihPD8FfvQICNc+0N5DZ4xU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}