SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3e9173a6cc78f2f96fc496c535f7b515cf449f7c04bce5d85e69baba338b87ec' 
  AND token = 'NQu8z/LnOXo6RkQtY05w+OPNRquipvhKVbhaUuJ1yNc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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