SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '29f8fd93e3e83f07e4fd82cd2f2bbdcaae2caf9a89350bea982f782d7556393d' 
  AND token = 'xBBaVwOKUX1GMSjOg04bL70xsBCi+xgOZY8zioi81bE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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