SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd6edf12aab7439e422bb625f275f96cdefc2c02f5fc4348fe9b5faf641fb1c14' 
  AND token = 'uQBPNWt+zYvrEMbbpRgOnHaOM/LXqeSBBRswvJOAkKA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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