SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7271af6843f06e310ece3c3c95165d7785b71eb1f72269729120adb589316942' 
  AND token = 'HxJifCIZISeMzYHKIVHsoQB3AsJH8wzdK0GqdbpVzVs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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