SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aae18b317f2376b2b8e72870609874dd9295caa69feaa63273b06625256967a3' 
  AND token = 'dwj3HKjIDIglIAehSBFfmNgIs/Tg03Gkl3iWws5sLtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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