SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8fa8dd43a6a14fa7b198edb18388a95c676acabac9d90c32569c95a7e184c93a' 
  AND token = 'RaOUOaHld436zCpziHDO29m0B4Xwzm53mGNtzxOhnBg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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