SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9d04bc85b0502852f530b983490de4954d7c987427d47aad5bd4fb4eb0833c51' 
  AND token = 'He6WqMY6/fOtOKc2fuHYZf0ep1xbLuTOiEPnrcOiZRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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