SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '283845e156163511b5bfa33bb25ee17989ee135885ecc0c9d2b80578187d2f6f' 
  AND token = 'pXOLDptvsmr0FG07lpDJsG6BYxsSZZcIt43p+SCEs+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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