SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fc5258b568b5e601d705cfb140ccab2b7f6892a640fb7df7cdfcbe4fd7f0e57e' 
  AND token = 'ZJVlIm89MY+7b9zOvllGv+fj4x65ZKyfmv6rqHgAw8I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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