SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c5f3fedefd297c4ef2439aff31538d0a5d7cbb88a0a6e7a17526bbde40f5ba21' 
  AND token = 'hMmo4EYcbfWxWTSheJGr/9qyu/vgaNAvva/pRF5h558=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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