SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da7645fa083b4f337fc1dd5146b80f4e53e9c0cc4da4616c63be7a4743dc49e7' 
  AND token = 'PxUzez2lJy7JPrP8PYwLUosJJGkoFb/By4x8BtEU0Xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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