SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fd638b1c4e430ffcd5017da6ad9addd356694f017205a0ff05c76c13e2187ef4' 
  AND token = 'xnxFyVt9OOgp8EPJzrVfq+amxjzV7yyJ507dbjfTmZI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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