SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9b8b9644a8e742f3c435ea64dfbb52e4b701a4e8bbd2471337f20f930ac1e0ee' 
  AND token = 'x9nB5RnFABHbcyhl72oq4JPeJc69oOKs1rCtYmIrhjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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