SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '71c29c6410af1f47e3efe096e77048206416fddfc849f1e1f21a17d46ff12b05' 
  AND token = 'bvghkEKbTPbniclzTbL7RoCTOnW3oFAUc0USX9NnudI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00048

JSON explain

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