SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '076f9818daaf9541ac93e73f6fc372ea900c03fb83e691e016d6c9894d9f560d' 
  AND token = 'Zsdz+Vs6SDK5ZixQDA8COfKBTV+IPnMAgVTxyio/LDE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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