SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '192d33bc5e33449752f7b5421734156308f336d53c8535d0787ec882590fcdbd' 
  AND token = 'CWswNPa5U/XqnvPe9RnVoNWmWzkZnHx4SQlBsHOtRzI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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