SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da7518df8bbb734a3937360d5fa74fa0d9a918fe728b1c4cab59fe7c8e3c70ac' 
  AND token = '4PHWJ9Ltf9Pq8QvQejdWLBhEK61NYW0yaVA59SxObC8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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