SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e7dbcb795dade07a8957ad63a7f9553f346eb5d45f57a548a80df7003d59ce40' 
  AND token = '59B4FZY/tyoCqM6HFHREXeQFKCXqCt+f7NimrM8MVaA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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