SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79709af4b5560750ad05fd7734dedec2c4f56623b8b3ea0077d20ab4d1417b7c' 
  AND token = 'dSXul4k4PQuekCEc41mZ3Oyvfk/5goWL1J37bZf1jhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

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