SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '46beb441a6f79787392b794bd9b6517ef977e7c7bb84f664586bf52ebf3205a1' 
  AND token = 'BelYg/mjriQBE3aOHOLBEDHiVOZ+23pXlGOJiF9zZs4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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