SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a813389cf078f4197c06349cf193ebf6a6d19155773c92850678b801230f2aeb' 
  AND token = '8393/jyRO41k3uJ0tlPKKDp8SezTS/C8ZTTvpmjib+4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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