SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76f754994f2feebf2af66f6162a5271d8743b9d86c69cfec2ac431fb67f6557a' 
  AND token = 'VqfKL8miiQ7ti1pWoRUYw5DCFZnuxIzh99aMNnpRHQw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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