SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '518cbf5f2dbeb8c6045f41e1a840494cf97ecb0f0d9ebaebd0bd9eb4bdba1aea' 
  AND token = 'cFr399OgGVdkumvCzkRLrdRqShLef7hfksNI7grqJSY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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