SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9172bf6e5adb416f48afe8ccdf693b19128afa27b934b2493b5f88b0b72a4761' 
  AND token = 'vbUIJQBvl2MGPw94EtQsXuRjDEKyzwL34HgGMdNBR2A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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