SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b282773c227b504b7d8a8f54a49a782c2a2162f53b5e88c56d604efa7f0f9ab' 
  AND token = 'UWEtXFl+TZH4cBjKLbcgaF0WPDbDjj+FrYtaj2TcDfg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

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