SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd7fa98d1c136a46133d4faf735b282d3ed019b572e30d96e3c9c66963bc21319' 
  AND token = 'uir7UyKybJ8fbVic6+sYVDSPapdG0WgkMXsURksoTe0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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