SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1d27d61865f4e38b22e5daaec819d1dd99c57daac94a2222d11126556b939427' 
  AND token = 'iQUyVBzOhnhMmbDZBiBRWLNj+C0g8WjKpzBJSggI5XU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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