SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd695347f36725f8f135c9524b096813507c7883021acdc2416c6baa0af27bad' 
  AND token = 'KHpf83gIsS/n9wW18D3IsrjGph2lNNIcCj+NPeKn6CM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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