SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1830f21fe5fc4c56675f83caa2cb9ddc1dd24a94870bbec66b1274c3890a5058' 
  AND token = 'yGN3AlBGpwDxtbhkhEUlWrWwHd86ggwZ/vbSqtJK+jE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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