SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd19e2169f61fe99295ee54fd46ce98a4421009c8ae2d2643dbbdf2562f8a31cc' 
  AND token = 'JvSKY1piTcXed8BkFGy0p6AfatcicqRge8TEwKrejqI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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