SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd2beb6f0b272e045b7a7624096df22cd81d782ce34e8078a9a67291443354bdf' 
  AND token = 'XC7pdPBtYtgJTmHBXNHIwG3wHvqkD3B44YROo/qoDzE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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