SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58083fc5d1229f953733514b6e533537511218274f8bb28714f2932c6526c8e9' 
  AND token = 'Cf1lX26XI/NjKDAUrV4BVRLVD9EWpXuUiaoGVQsNbjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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