SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f47fd985e28498563489a75e1fac15d90f62cb23e14337a96b6fd47405d03467' 
  AND token = '389V/oDJ/gQzYaLZKuZBThWxD+GtgK7e0g1zX9/Ti5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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