SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3840b720658864e67f521a56a1adb662072becb797d70f4b041e1622f5139320' 
  AND token = 'LpdADkSNZMpDNzcR7jpyRAEcC/mfrvy6kjt0atsUSco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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