SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56e73b88a4e2d8a5436d5f5ff2af55331dbda46788913374a71799ddb4741d37' 
  AND token = 'habQnGqo8rPRr0NPmX35Hi1Q5zaF67oGbuLd0sqsMrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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