SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6d11ec6e5d0db43c405085c41b206fde35a6c6304a53b913ac213e0f3fb12a55' 
  AND token = 'upMdlSt9qJhu6SbbloL+/Gtl3EUBrgufKJPTcM9HQfQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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