SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a7738e8ca5eca7ac1362ec4b04cb40c6cc86d01128106264f83c95395a58764' 
  AND token = '8ZXFg1MLXDOmO4vCrbnd0lQwH/ZqthVyKZYnAFp//F0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

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