SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65466ecfb64518b0ab1269046ebd6543627ca285034e8ae24f7a8a0b494a96f5' 
  AND token = 'KQhtsWQczHLt/eJMdK6HEgNjG4aLbt7jsh7kWypn+N8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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