SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '551aacc3c3fa584a6c0320b03f3df04bd251b38f89ea6d7f75097690e8829dbe' 
  AND token = '2c6po+RgPccId35QsnGwx5VLOUuCXigAxuAMM+Hz6ag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00014

Explain
id select_type table type possible_keys key key_len ref rows Extra
1 SIMPLE Impossible WHERE noticed after reading const tables