SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2ade9212c3fe66de89a077ade0cb2726905d73260612acce82c13147d81cd92c' 
  AND token = 'zfUEtmqdJVmDz9y/il11fQQ79XHWkQydr5IZymmIpC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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