SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4bc0bb53839c9776f5a8820aa8323550d69fee73ea16994eebe2f659b8a6175c' 
  AND token = 'igCAyKzjbUEox1ZRWrpWB4aB8QjXYMg1l+54gJg2mqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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