SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5e4f9914b690d8ce9a930c7216f4903ca5e83445b1c33467e591eeac18560c29' 
  AND token = 'ppXQktbb+/9128mSM3+HYK1xBt8mOvungCywnxTBj64=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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