SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '644abdc619049324d5c25d68e90d43c8069734c24c5cd37bbc7233dfb7a830f1' 
  AND token = 'yZYXoGauV8UnCSG9iaD1wuaJbngbibc/adkdeV+kTIk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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