SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a7619fd1f03dbb26faed6de62d76a4ac8f5ac6a873a543478a3145766078a040' 
  AND token = '5HtJgqUpDvSIgnV7hDb7eOh01i02bmzY6hB8Od02MUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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