SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cccc5728084be671de2af9d63c0af2658e683b28d070454d19c09ea412461d2f' 
  AND token = 'znjD8EoxybwjJMb90UQ5BqS/3BR9XCkuff8NKC24slM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

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