SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '0da001c49eb8bdda670cb9c66f248ead6fac91d29d7f22d8336d36d135f92f84' 
  AND token = 'YdmE//d0QWprF71kUen2MpaYnOz8NOGXdKQxu21wrOM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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