SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cbc08111e5a3faf44fe680f99b3798d09ef8b016df21c25e1350369fd567248c' 
  AND token = 'AzVotKOrg/IFvlM7arRKmIvGJCWVRc/FzcjVT0gvDQo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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