`created_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP,
`updated_at` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
PRIMARY KEY (`id`),
- UNIQUE KEY `chain_id` (`chain_id`),
+ KEY `chain_id` (`chain_id`),
UNIQUE KEY `source_tx_hash` (`source_tx_hash`),
UNIQUE KEY `dest_tx_hash` (`dest_tx_hash`),
CONSTRAINT `cross_transactions_ibfk_1` FOREIGN KEY (`chain_id`) REFERENCES `chains` (`id`)