SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '83f5323cc0fd7da9adec945552c9981123a53413958deb6993895e0594bee7f2' 
  AND token = 'PXtpxJzBFBatfnYjtOqXVfSOpxpZzoDKmM9GC0E6YiE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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