SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be2b360f61b9ed17f28c783a849ab409f6f108b8ac9fd8801b0d8066b20a1805' 
  AND token = 'QWL1VTru7z/RDU1sjBmlPcKX/uiAmwBJCwa4+wcdqZk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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