SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8c858b933719ac9571a92bece8a68523d59360fdccde48f3adb06d12f670a31a' 
  AND token = 'D9pllKjOK1Gp+HEIVFbVmvIrT37Sq9+ozqc5sKWXaWQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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