SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '533e1655a96c1276ea971be17ffcd57e592f1f9eeba853b4ab2e02501e867d64' 
  AND token = 'yEP1IFaaCCM/WQVprao+8QIz7zfzHtqAqRTEmWzZt5s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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