SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a796db85b400949c768affdeae9d67f75c8faac4274d598f7976d8b82e320a66' 
  AND token = 'a6QCehn+sHbBVLNykWZLeZz9DD74LGYKaXah/qGikmo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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