SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '96bd89c3b63d7e603f06987d393c63b6d8d93e25fb78ec7b330d4cc7d2d0a761' 
  AND token = 'JhHK1/FWPGUy6qFY+gHznmMwzCwbg5YsCoTZAt0mnkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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