SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d0f8e653bd86cc6f61b1308d1a824f9ff491b4d7ecc72e2979cc46d727a4f04' 
  AND token = '7a9QjGYaD8SbDMyWvp9skKnT2EiY0sQE7KgucBU1jUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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