SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a58943c3b4b9eb521a06a25c97eaa114f2580f76fca8c9d3a6bc83c30a846260' 
  AND token = '4b5+j/YdHdghLCI1hCK65MBQmYOAp+zXmyKE3HuWTn8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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