SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3843f0f2a49ae60027273c31fe0ba0695185b277d6994f0ea6af434d7fd3b438' 
  AND token = 'NwwNJlWmm7az2mFGXP/1ZFa9OKXu1ZwgthU0/6t5mtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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