SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72c43f70463e068fdc473111ffdbb64859750be802e7887993e955de100d3cb3' 
  AND token = 'crbVp+5FAvUOT4/uJiTZxGQoL/e5uxq8Mma8MmbWRGI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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