SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b8c80db524600a9c65e136a79799c5102cae5cfd74400f62345855aa5316c71' 
  AND token = 'FTaomLWCFbpYavBAqDA24289u0CJzg9QwrcLaIpXjhQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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