SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '57c271b7149197b6f6e151cb6d9ccda174b723a467d42e66b59cfab302f3bfc6' 
  AND token = 'KoEX0uShehbQdoDzZkriIgHh1xVAkNxccLxmRcoqvjY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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