SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '170378c3d30563a19872f0a42d298c57e0f2b7606561dc54ad6352d024cc873c' 
  AND token = 'rboTUX5wUGzUI8/OzAy3O8jULbYZyQ3be7NqwLR6CPo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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