SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fde425f0f1716f36d000f7c082a8f07168d8434ee5a841edfdb593a71bdd6acb' 
  AND token = 'a2ZoXQRpziTfHRaXngYzmrFQiu/AqZdPu8rzvUG5UdA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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