SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '801a6bac735bab61605bda923113cfd5b482068549e0ffd4c46e29252c003673' 
  AND token = 'yVJtMDTS/O9OeHCjAHJFCeHaRpzfTHdFNa5KBsAtuWw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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