SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e730d6ce34a3ac5192acda63f4153b77993b1b726a09acd92c56736a901f215c' 
  AND token = 'Dj7lW8PGoyfSB5M1PHZs3UlLYQfZBoszC106cj/NSGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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