SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '707a20c21e221b7a196cc65b84f8381e6d2864e0824453fbff07b118fd68c198' 
  AND token = 'w+C2bXp8g3dHOQQVm1RObd3K1RxDY/dzGRIpKrUC/8E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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