diff --git a/backend/services/mining-service/src/infrastructure/redis/redis.service.ts b/backend/services/mining-service/src/infrastructure/redis/redis.service.ts
index bf395c69..1331db79 100644
--- a/backend/services/mining-service/src/infrastructure/redis/redis.service.ts
+++ b/backend/services/mining-service/src/infrastructure/redis/redis.service.ts
@@ -64,7 +64,8 @@ export class RedisService implements OnModuleInit, OnModuleDestroy {
 
   async acquireLock(lockKey: string, ttlSeconds: number = 30): Promise<string | null> {
     const lockValue = `${Date.now()}-${Math.random().toString(36).substring(7)}`;
-    const result = await this.client.set(lockKey, lockValue, 'EX', ttlSeconds, 'NX');
+    const ttlMs = Math.round(ttlSeconds * 1000);
+    const result = await this.client.set(lockKey, lockValue, 'PX', ttlMs, 'NX');
     return result === 'OK' ? lockValue : null;
   }