SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5cdf6532b8b44b7e08dde5c91615b160199a8654875ea01218b3e44da1011497' 
  AND token = 'kRDBcXfcPOlZUDpQqKjCfHpk6sZPW2BbZKF0GEnZPSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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