SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb79331bbea23218f63c1289d309608ce300184c3858072b425ccdc4db58cde2' 
  AND token = 'gGKjD7uL5QawDaHglKJtQuX/OkAvPfDtY7BWZkHvID8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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