SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '487019ffa3af8b372c45e249de9f9b9ac62a38eed54a4bc4921a71863e85d587' 
  AND token = 's94t38JgjNc82N9I/CBos3W8n7jJDp7rvr1vbK51i9Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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