SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c7c637aa295e47812de709d410b995e959a335b735706b39928cea007836f4dd' 
  AND token = 'c1UX8r9GvvqRUzbuxf8YnTJKxNFRMZrd1X2pYUZY01Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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