SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ecbf29e0eaf59e345b3fc9c58648b7ea5b3a289cc026cafb04451e944584b27b' 
  AND token = '3OWdZNhMMdsAY9pBL8OjAmWLAgtUuBKOKbL9Xr0JpZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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