SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83c3706f8966e4d459c87c7087c0500aae62cdf563a70e7498cb435ab9f3ac13' 
  AND token = 'EPjUcXQOTsSUZMSlhwItktpC0wKEsgtLaKkfCI7im8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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