SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6577897296dccaf6f3cb1cfee660d0054915daf026038f5d623aa13e5079a954' 
  AND token = 'xglenntZQ1cizIta1y3qfLxU09iVorER9pLOHd8psQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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