SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08cfb97ebc895f791df7723bdce0c1bb6cb8853b473104f197cec03eaf28e9ce' 
  AND token = 'oS3UQ8+EykpsZKJ4QkO7vI9LK19HBjgy2fmOTpOCYcg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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