SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'affe38e35a848009a0c2319e92c9611835dc79ffc6e13dabe227a39e90599554' 
  AND token = 'jMh+hcidwHQBZh7g7e6qLc0jpmI6nzyoAEwgGIHVLm4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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