SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '14025c8cb63799226697c3c114e78dcd2bf787fca2911beaf1af5a594403f3e3' 
  AND token = 'YvqFHuRKCM/xD5VbNvtOuEW7XNIi3BwHpKz6si2PAVA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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