SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6661ac05247bde1606dc88444cfaa7fb6fca229c549e34d1501f24a8bb8cfc21' 
  AND token = 'UXzJxcH+NvR7z/7tcPj+no4dCLnE2oUybeXehlLXypc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00064

JSON explain

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