SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdc9392a57b6f1b2d0da08c1c8c5b352397cbd712445fbfed86b61bea8096b14' 
  AND token = 'ZsK4ycoQzD3cTThVmKsiuwqSG8XSixJoXwn4ksQff5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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