SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7578bc25095cc393971e5fc95f36babad7c29d194f3ca63d834ed45f62c697fd' 
  AND token = '2mGlsYTK6eX2x1SdyTCTC1wXbnYhl1ZLtciKeVXwcCY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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