SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '772e8a0211c906365764df004dac65de17c507170a2f2c91d45680af7f4ef6c5' 
  AND token = 'MV+o7aJaMbtgAKrxpE58Txnc2qWIYF4yLwYjoPbMQdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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