SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '484f1bb17639400770512cc2aa0ee12507a4559f78dc256dd292b8f10704dd00' 
  AND token = 'toQg2TYB7EErRbX5sgulOPAw5V0k8fSleIG7i8NxUxc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}