SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2977c405e4b55491304bc921af3d0fc395b128e260ca8b6e930bcc7f9e3b2bf' 
  AND token = 'y5k07wppV2tVYnOfIkarGVlzhQePBLxy8I9gqW6n2do=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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