SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7846f816ca66adc4502dc5a8ed51452e0eef24bba1debbc54226815037dae8f9' 
  AND token = 'mByRWRspVuWaZ7WUTgoUCtEL8JTi9K2QqFCJ6kbMC8k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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