SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff1e8c44eed5f007f651a9f1a1c7087a7bd96156dc49f2c9c634e0d43e0326db' 
  AND token = 'ZKHCJ4hYcxnq+HDTLOce4Bd5zw1iFu7l1+pdYGfIwJk=' 
  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"
    }
  }
}