SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '765d46e03a5f3a25c7c45ee2a6ffd95db1366973c02f801fbc3c48600f871db3' 
  AND token = 'hSXhUBRa/DPXc+OXU27Hlgxcyso8Z9xJjSbKb9BNkMk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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