SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '64cf2eccc99d36766456c8860658d9e295b1cbfabd86cb469a9dfe5c51507534' 
  AND token = 'wp6xDabxZ8BORnaOhBjo7glUobX7Ok2JKRPYZXqCPFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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