SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d7c2366381adbe01c2e9f19084f639c26760964867cf9e132470f940bcee007' 
  AND token = 'zmqU1NwwhuqCiyJMH/7dAZkhcntaq9KXhCBVODzYZco=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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