SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b56400530de07a173e9ac64cba4a578434dfc08e1ae82614aff6e016e7f5360f' 
  AND token = 'Uh3DorbUomURkmzgqWqWunfTiFGLh3PVwsIIZOrqv+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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