SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f1f0501e64c74e97ad6f3772ccc1c64a40b845162cd93a3aa36fdd7237eadcf' 
  AND token = 'To3RsHAjOpf7Xkg9IiOGGP6TbrIwzLBUWdVd1VZhWtw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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