SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c96b4d323c3957ecd3a0549c5d343c8c9bb1e2934745310ff800cde3ba63fdf5' 
  AND token = 'ZqyNsYiTJ5pF3mYBQUg1gkQrTpxQbLYkr0zkttBHSRM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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