SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad8543215f3857b5bb294ded9b33d773473431a41633234ed26cd6563c0f57f7' 
  AND token = 'dI6MIttediGb+PJ6IcnZQ5Lf8fXbRUBVvFruJyMWIbE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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