SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84bcae00402081a96b62b5286377f36655707d54f6f17ce1fbc150e94bec833f' 
  AND token = 'IuHIxrBqyp6l9zC0fsfI48WuU/O/V/2ME1H+qvjzDRw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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