SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '439edf2f7794ca24e67536efc0af74faf4945d66a794a36945668133b486f9de' 
  AND token = 'iLTWdUs6buTyqweKJHVK9tQ7KGe2cnb4PnbSuxHh2nU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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