SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb113557d9b5ca99f5398405cce2b5f99c7e2464d5e594e03a671249ec927650' 
  AND token = 'SilIcSSY8uDueAhNQBtdGB0Ts3Hk/vjwkkH+XpvDMTY=' 
  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"
    }
  }
}