SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23cccec499f2835f37b10644f5725db54255c20daae20ea78682e79fb18fe012' 
  AND token = '8ZR4HsU22Ow3W/ZXQr/2GweRs3N+5NgI7N+RwZeAz5k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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