SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b87bd6a6b97a61d0d24963fc4c3852cc09687ee454f91d29eb9ceb9ba8a82730' 
  AND token = '34ru/jhp7BAmF0U6/yiXQgVN9wuY1wFLWNoPyt7PzGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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