SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '482c7c37e6e956f52d9c508369e2b6cacc68ad544fd8e377709c622a0e197ce4' 
  AND token = 'MgPYRgt8PzuOu3xmx10kfbERodCnZIrkcMjqtxDfQjs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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