SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10175df290a20262634d036c1811e2c42f808839094c3a5fe2106687dd824cc8' 
  AND token = 'TZ84+yVN8G9T+eIyGI7jMjOQ70+CT/ZnXUt2UIn9I/c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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