SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45f52713aa17987c634519af8acc5f5e7b8025e093d1c2776597469b0f5ad601' 
  AND token = 'afJKBiFvpZGXToIMbxYL4/bstX0v1OngDMwymluTCBM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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