SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a810f0332419a306ee604b3a82da635d462ac0c8f3b3f7d1b42b97c02cde4eec' 
  AND token = 'm8AJr6JEbzgrwrv+EewviA/L1Vz+jiKgua5O46jqt3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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