SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55162104ba110da5fc0f527a01609912dd6ba865a13379d71cfd6f7f87ddd392' 
  AND token = 'YsYhjkfXIjWRDmoMsgCdHfy/DRuzqMqZ/2QptgpqbsM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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