SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3f9cfee743f60a888b9a02783039218cca67e4f56412b52e6db34cc03076c520' 
  AND token = 'BhNxZ/qqkbVPr4SGI24B9CXzM7WOeIdUf/of8/SFmVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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