SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1651170beec013d6f6c39bb13603d187f2eef4bd4d33cd4a25c5b0d0172eb708' 
  AND token = 'uKz4YV4QXvkfqK46EiMKv0MP2Cy9IsYSd5xVRV2QPTw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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