SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ac676a2e291a2de94d66b991267737a37b861723ebdd6fae34a829f52d3ccc4' 
  AND token = 'Vv2YglJ/11A8OdGPKJu49gzlFGdZ6vgX8ohRI4S/CCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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