SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc5d58ba30a54a05c90c70e6a4fff5b11adae9b50aeb40ea0a6280b67e56f57f' 
  AND token = 'rkFMwweJHt+ij9Ck9WyRQ4o7/r9DHPAEZS7N8Pjw6zw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

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