SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '853f522bb3f70148464c676cf096324663ace9b237f4329baca06714220e9cd8' 
  AND token = '6oX8VuL8LBWo5RmDNYa6FVzLVGK+1+joi6K0K5xjJPE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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