SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c05fa2b86878c40f6bb97881f7633cc4e35c538950884299c6da26f09c1b6e62' 
  AND token = 'RoZszG3KvsDh8fYTEB9Ede0c0wDZGJPTfKZUb7P8OpY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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