SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '44c663be38af0ee51fbf1dd2e6ef7966076968d674a2f2b3c141c782158caa45' 
  AND token = 'LmkVmlpTsbdD3vdmqMfiTyZbr7m8o0Zx9hOuLXBpCbg=' 
  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"
    }
  }
}