SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b446591e9ceafab56496b7131c2fba04c037eb1758b7efa3417c7d0ee17fe655' 
  AND token = 'l1aBc4NDLnKtvaXV+KT+r0JvnKTMaTEWS0hdqrjc1y0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}