SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '933c8785b5777253fcadb64480bf89997d88e3942226575b5a34f6dfe512a8b3' 
  AND token = 'cyaYp/0eAO1elOs28Ui8lPd8+8+Iojk1Nfrsihk9GvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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