SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd626b4720668a4b9b723d6c50b1677f80d1fd63529934a23786a80a56e69c5ec' 
  AND token = 'sjSCupuON6bGqYBq96zNC9AtYauDvDRwAzF/Km//3b4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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