SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eff2670db56a40e55cff40359d9013cd87f8955f02fe6fb49940e25cb17960e7' 
  AND token = 'XzBDC+7buj683XnoYrR3RDEDh1ByrbS+KlmB4Hb4y6Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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