SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '704ce652146baa7b9dd9ad855337f0a55e40ec5bde8131273098447b77396781' 
  AND token = 'tsPsIcjeDYjHOJRU5xzG+/gIDUxNRK6ZeBbrQyWMzNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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