SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5779704b14cc7c51fe920f02c8136af8559bcbac8fb077dda8ea2f0a22164d60' 
  AND token = 'DJsTN4MaRUQC+V8KgltDvNPKkR+fcKzKVyy/MB6Lna0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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