SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b8544d7505f106ce1b5768a53bf4f82c1cf9a21cb1284f9bd480b7a9a767cd2' 
  AND token = 'CfdIc8XSIez4b4h3ye42zh0OV+kjAokdPugkj3OLUWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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