SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a1f997a910d19a86d2c6715357501b52ade0ca601287aa9f858ebe057c321fb' 
  AND token = 'uNLmTfBZMjScRYmaoCHNGxdaat8E1S7LR7aojLhkiUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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