SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd00374a7de5f34d3d7b95804c804bcb41a9f61c6c0b8a980cc3d9eb54324f0da' 
  AND token = 'JC3zTs+5XlYIvlnbnfW6tRqlGC0wVEKcmshYG2M6BXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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