SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '98f713d4263e29ef9fdf784a8597dcb813b915bb81e9c8250d20816316ac3ede' 
  AND token = 'sTZTGZGCheOBfN0ro+ksT5S6VGt1YDjZJKRYJClzaJo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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