SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a206ab71abb9637b5d40d9c8e9c35282e6988428cb09b4458589a8a331c76c1' 
  AND token = 'mREqXUbw/vJAV9lDnnBcFB2+R/HmkwzYf3ivGRlVk+U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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