SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b173422a814fe9b210c2d99f29bdefa79ebbc28b4174aa716c538dec763eb638' 
  AND token = 'xNpiH7YQDi8ekHPXB9kcsR9jbpTfneWE34oGnEJKrU0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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