SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '12bd01c069d2eaab67de7c0f8cb0c66dea236adbaf167c8f87a4e3a795734bd1' 
  AND token = 'DxK2PsO4oGAL9QiECnbZ1o/+BHVlEle6iqjaOT1GUt4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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