SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'af29aa919d91860444d375f8198877d3256686b6865cf36ebfd95331d25f3ace' 
  AND token = '1gxIgvHlUg6Z4a+ZI3+Pnr7xwhvHbXZkI0t6UwYas2w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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