SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5da822a78b9402b639b57e8151f381523966767791ea5aa6c5b8c324fda0a674' 
  AND token = 'r5Kc7U3EmeJYO34rR9ZCPlLqS8dgx5yowt4vow/roYc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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