SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2d5661cfdf21100fee26e865d55a205c8b9e40e6430280d1a2ba63239eda7fc2' 
  AND token = 'FSWKi+z438jvLML4qvEL6fvUY7QwZdrqlrC7EYRkeBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}