SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4b3992bc63a79ec0a1b70c0f08b88136b3caa26b9e6b9f50cbdc2876af511c47' 
  AND token = 'nlEB+Zk2bKglSxE+SVChNJiJt6m+okqTCAsGLa4KD0Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00013

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