SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5790ea47746319533284b2f7faa21179830aa6152206e6152e95ab295e7c2d12' 
  AND token = 'aIGgyjqOYCR3ZgpY6KuIbCWt+7ExIpOAjD3C3UV/7Ic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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