SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd9c8ff00f8836d3257a3f752d42a82266a4a495b9a8edf1f08137ecb7be95f42' 
  AND token = 'MflGIqqLU1v62KFRZawDJwSHsNO8RxMXEQQ3gc7QgXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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