SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '261a9fddad6fd226a8ef0dd5afb55d3d077e1ab9ef4b4b5de2190db2cf3592db' 
  AND token = 'vZExbTa9vCz1JgpvOKzuK70hwaEYNyLAnLLwZ0yg5UE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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