SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '37fb38619b5ee2f99b7b7e71eb4260b3a988e26dfca8b4debf05f1cea0d09376' 
  AND token = 'IwAXh+kX5RaBa4DBkvBnOi0zAZVDWmONk5SQKg01LyQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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