SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f831b4671259dbbe7a20bdeac7dead8759c2c1b7796bd4c7ef771c21cde28156' 
  AND token = 'Fy6QnPlDLyeytgf4cN696JxuyUaSSBDJIUphpf30HrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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