Locked Scarlet Chest鍵のかかった真紅石の宝箱

A sturdy chest made from scarlet with heavy chains strung around it. It could be opened with the right key.
In-game description

What is Locked Scarlet Chest? Features and uses

Locked Scarlet Chest is an uncommon item in Core Keeper (Placeables & furniture). It can be obtained from Fishing in the Mold area (non-fish catches), Fishing in Azeos' Wilderness (non-fish catches).

Locked Scarlet Chest key points (from the game data)

Best source: Fishing in the Mold area (non-fish catches) — 2.4% chance per catch.
Sells to merchants for 55 Ancient Coins.

Calculated and summarized by this site from the game data (1.3.0.6).

What you get from salvaging Locked Scarlet Chest (Salvage and Repair Station)

Locked Scarlet Chest can be salvaged. Salvaging it gives the following items.

For each material, the amount is "amount used to craft × 0.49 (lower when durability is down, 0.3 at 0 durability) × the item's multiplier", and a fraction is the chance of one more (2.4 means 2, with a 40% chance of 3). The range is from 0 durability to full durability (items without durability always count as full). Scrap parts are a fixed number set by the item level. All items that can be salvaged are listed in salvaging.

How to get Locked Scarlet Chest (Fishing)

Fishing (2)

Source	Type	Biome	Amount	Chance
Fishing in the Mold area (non-fish catches)	Fishing	Mold Dungeon	1	2.4%
Fishing in Azeos' Wilderness (non-fish catches)	Fishing	Azeos' Wilderness	1	2.2%

"Chance" is the chance to get at least one of this item per try (opening one chest, defeating one enemy, one catch). A "guaranteed group" is the group of a chest or boss from which exactly one item always drops; it does not mean this item always drops (the chance of it being picked from that group is shown in small text). Only items that always drop are marked "Guaranteed". Fishing means catches with a fishing rod, separate from enemy and boss drops. Calculated from the game's drop tables (Conf/Loot, 1.3.0.6) the same way the game rolls them.