SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b5d317fa2e208c77e43b1fcb5fd4f4eaa429b66a1808ef57e3487b3c32b9c68' 
  AND token = '2bWcy5WOj5GsYU+6fUophOCjuj2C8lYXs9Dv7JmOVzM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}