SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f68bb2bf0fe8114b8bbd83bd7a96e7687a26597285c4a50db04c43a0412a39b' 
  AND token = 'F428S2HynUmhgJcWwu8qdFcI8dq8zJfOK34cSmeW/Fw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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