SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '639deda6e1f378b4c4cb92029045245a7dffd79f183458fbf8e05b8a3e4ec843' 
  AND token = 'U6rsqse8/kyavRqJNUg62wrdymkEiwxI7xpyxc4xXqw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

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