SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd845a6fd36f429ddb03e41cfddc6b8043a175a9ef50fbe16b31689fb49a5cb0c' 
  AND token = '4Nhymc64BTeZoHBP4o+fhv2EQyqs+vYqlh9iePH5zlI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

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