SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97b234aee1e113531ba6a8e4c4f22008f4ff4a1d8c3b3b9f1fa268bdc5282ff3' 
  AND token = 'YDNlUedJ6bBhCQxnAT9O/SqyMDMohZ/543jGE+KhEzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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