SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '194e437629d25a4cee6bc185ae5ed55baf54d8fcc167d3401324b6447c3bf027' 
  AND token = 'xgb1KfUVZg7vdRHu0wI0FhvcNX4sPwcyEzVGOnTju3E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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