SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a57ca31885f1eca31ddb14a0caa804ec10c835ddcd90b5b5a153b12a60af3548' 
  AND token = '4n7oQKF+KZ6SKKYqiR/DGN904fl63uAtTYWtaGMtbsI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

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