SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd47f8e094135ffa00f4f91a0fa882bf7819ae9965629527a4b1d4f42e84f77d6' 
  AND token = 'l1A3ncSQ4M5dWNrnQjJE6V1MelTVka4kG1+05sRYh6o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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