SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '71f08afc1d07f26762f438af98dd60020594a8faa233685b8fa37fb420895b94' 
  AND token = 'zZ01XE3/iFf73NZSmfmGZurzAStCBge2ZBOPgozqPx0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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