SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8777da6f91fc17b23568d72fe98186c0af8802318722ecabd672ca9e8f3c6787' 
  AND token = '+WWQSLWck4MayGn7EOSiTtKsWfAq+bTLeclEZKcXbyc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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