SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '214cf6c8fc90cdac4da0a00920e638321b131ba3c24e8ed7325a8ebaa9d208b9' 
  AND token = 'xbrJdCiZd+RQtUL5enpwHt4BNXEnjdG/4tYRJsu7QXk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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