SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '83abdf7c76024f5742754e17ebee0098aa793df019ba3ad911495319faa899bf' 
  AND token = 'Jvj/vkIFqloK+BOMFImBi/z8N5LhOtzKR4BFdcrYEvU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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