SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5216e1bc1fa7285211b62431711edfbe5f022dd70cd8bcf86d96d04d40cf41d' 
  AND token = 'GLeBcmIHNgIBbeObVwQvdhHmfEruzkpPVirAI0wgGGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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