SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9bdb31565253838e5b662d62bbcc961d80e1853d9cf5cc0a58aba8f37acf6197' 
  AND token = '7ihPZ+Au7IyDfmDItvpO+SOBa7StpxAyx+k/0kqxQJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}