SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e77fa3298ca9fcb5b89ddf915c3fb4cc7f4bb23e726bf333cbba78ce1385524d' 
  AND token = 'bZYdIWoRYNFpP4JH9xXWwIpM/hZ+947BFAcquP2PoZg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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