SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '04510f39fa86f3e715b457a702f75440a97f5faab41db52ad178abf514b6e5a9' 
  AND token = '/YACh87SFSnl+J/6GoF/Hqcg+ZzUCrmLoCshqK0HR9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

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