SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cdccde7a1ec09fcfe91e96ae46648f10bb8b55e3dc67a3ef3c3c40e35d99bdf' 
  AND token = 'db5ZFnlEtTpXgbm//2Y4PQLePpCv7e/P9MrJNV5/wCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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