SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '561b73a7288cc7a19ab2864ea473374485a3fad6de6a4d7ff46b020cf8d9d705' 
  AND token = '+6ehYt8V/XKsCh9QLMow0URqrxjsTk5QnzUT5svZwOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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