SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'b80df62567a7e57d3179c3077e9e581fe6a3cd598a73cad7610670147cd87493' 
  AND token = 'hn9brttRWAx5O24/5b2oyDOwYQDS9cxBc7gaymSdMKs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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