SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6e83edb691b2adafdf37934be202d1f4009ba126d6e43cb06fedbe6ba671eee' 
  AND token = 'DE6pwFLrO+WhwR0QZx29MPbecq0GKNXCfPrw/ZIFHNI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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