SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '681e328c373bb9717ca6af357b92a5712b5f45ee44267d2eb39bb085d2b52ba3' 
  AND token = 'U0/MHfiOcenGjZpMDVDwKuFUeM+YLpAYeLN+OfPV8YU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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