SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac1795f94aa06b5c0077e25c74f320fb25240cbcc637e2ce24dcdfabc87e6445' 
  AND token = 'KEr3XexZmahLWl019pQb/PltaFHlT8+sqvtFqKZb3UE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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