SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac780c53bc45a8e06647e4dc8458f0b371177221e0dcdd28e4fa44186674c0e6' 
  AND token = 'MD9koDX0D/CTbEQrjGeoPkuMvvjUh/LcbCmxKhCNzjA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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