SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb3b1dbf20776859bba9ac277843c6aca45156514b4931b13377f96cae3f69af' 
  AND token = 'hhC9Juu+E/oSKWyKgkOqZWJaYAJ/+uU1e+hrrHu9cIg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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