SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78579862d3f80cf0baa580368582527e00dd2f7f79ad7ce6d6a44daf16093908' 
  AND token = 'GC9j7QWAdMmCUamvhwZ5LNnmvLfHvjMyxoAGe3+R7MI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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