SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b9209826b88fde1d28192c41ed9e7c5f1925557df0dce21a19c81c0762d78c3a' 
  AND token = 'Ldw6vVtqdyaAF8zIjy1QpQeWOHbV1n+kCKdbO6r6ugg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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