SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd834631b13c1c1d61312e5e31c7c7c9bfb2d84e60225289c9b190e4a805f4fce' 
  AND token = '6sGWgm+QVT/0hE/JaW4t1wgfHRzwKx/Hd8qktPqM5DA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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