SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f9ed0dfb7155837ed9d53bf2db7e9ef21fb04629de30e391232fdb04849a67f9' 
  AND token = 'KvvQiDIVvaTeujAqpU1JraBRYb5GiaGYSHJKf+9SqA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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