SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'dbc6519560464aff99855828d241e738ca21be78527f07f86c3ef2ab968232b6' 
  AND token = 'XgYeMzdFUb4DCzqfS69+kd+mGCT86+0AJwqukBpR9bQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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