SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8ad4f34833d69473ce9779b817da0fdd83a3818529985ab88b84b44b3a93e338' 
  AND token = 'kQq/KQAPgBlU+R9k2gmRYfbGvkzJXBNdcYIZhU+fi9Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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