SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f69e56bb530fcca974c66e3d72bc890e36e7cba65a6211f9bb2614683db0ad50' 
  AND token = 'Ad8p8rv/MaVnQsN+VD81QV+JhNOvMAz0WCS7VkdZ0WY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}