SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34226ade4dc359603bf1691a75e9845aa794567370456a7ffaa176dedf6fb66d' 
  AND token = 'R5xOWLWN/xCF1dylh74uug4yH6AoJHGkkegkdfD3EwA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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