SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1bcbdc230c27a56c86c40c8554631d1ff17d4a89c15895810a83d448d23b197' 
  AND token = 'G5ZIIC+YrJSOqZBmRinnwerhiF53zYuqbBxUoMzZ0yM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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