SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bc85ba9addec0f1069baced1632b2a4198ccaf66d11ef5b27782c047e7cf8523' 
  AND token = 'QIAJM8WjmvOTaZatavIw8NcZBLXGOS7/mYFDWc75r40=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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