SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6310f2120761ff7771149f740c94d0a30d3bed039278087a628dd31341f0159d' 
  AND token = 'jOiV+sdiLSo0ZtteiCRllP4zWP/JqoMkPYXlhtG6ojw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

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